Electronic watch

ABSTRACT

An electronic watch  400  which comprises a power supply  401  and a watch circuit  402 . The watch circuit  402  comprises an oscillator circuit  403 , a frequency divider circuit  404 , a drive pulse generation means  405 , a drive motor  406  which, in response to a drive pulse P 1  that is output by the above-noted drive pulse generation means  405 , drives at least one of the hour/minute, second, and functional hands including chronograph hands, a drive circuit means  407  which controls the drive of the drive motor  406 , a drive circuit control means  408  which controls the above-noted drive circuit means  407 , and a control condition detection means  409  which is connected to the above-noted drive circuit control means  408  and which detect the control condition in the drive circuit control means  408 , the control condition detection means  409  being provided with a non-proper condition detection means  410  which senses the occurrence of a condition in which it is not possible to properly drive the above-noted drive motor  406  under a prescribed condition in a prescribed control mode currently being executed, and a control mode change-instructing means  411  which, in response to a detection signal of the above-noted non-proper condition detection means  410 , issues an instruction to the drive circuit control means  408  to change the control mode currently being executed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic watch, and morespecifically it relates to an electronic watch having a drive motorwhich is driven by a normal hand-movement drive pulse and a drive motorwhich is driven by a non-normal hand-movement drive pulse that differsfrom the above-noted normal hand-movement drive pulse, so that even ifthe power supply voltage or drive conditions change, a proper drivecondition is maintained for the drive motor which is driven by a normalhand-movement drive pulse, and which can also achievelow-power-consumption operation

2. Description of the Related Art

There is a usual type of stepping motor for an electronic watch rotatesin the forward direction only in response to, for example, an inputsignal, and is configured so as not to rotate in the reverse direction.

For this reason, if it is desirable to cause the rotor to rotate in thereverse direction, for example to set the hand positions, it isnecessary to perform drive with a special reverse drive pulse.

A disclosure of such a special reverse drive pulse was made in JapaneseUnexamined Patent Publication (KOKAI) No. 52-80063, in which there is areverse-rotation pulse in which two alternating pulses form one group,and a reverse-rotation pulse in which three alternating pulses form onegroup.

Of late, many solar cell watches, which have a solar cell, the lightincident to which is converted to electrical energy, which is stored ina capacitor or secondary cell, this capacitor or secondary cell beingused as the drive source.

In this type of solar cell watch, electrical energy is generally storedduring the day and discharged during the evening, and there is aconsiderable variation in the voltage of the capacitor or secondary cellover even a period of one day.

Therefore, in this type of solar cell watch in particular, it isdesirable that a stepping motor operates normally with as low a voltageas possible.

However, the reverse rotation operation of the above-noted steppingmotor exhibits a narrower range of operating voltage than for forwardoperation, and it is particularly difficult to achieve normal operationat a low voltage.

Additionally, because the drive frequency for fast forward drive ishigh, the pulse width must be made narrow, making normal operation at alow voltage difficult.

An example of a system for hand movement in an electronic watch having astepping motor in the past is disclosed in Japanese Unexamined PatentPublication (KOKAI) No. 63-58192, in which the rotation and non-rotationof the rotor are detected, and when the rotor is non-rotating, loadcompensation is performed by outputting a compensation drive pulse,thereby causing the stepping motor to rotate reliably, and to drive, viathe gear train, the second hand, minute hand, and hour hand.

The disclosure of Japanese Unexamined Patent Publication (KOKAI) No.63-58192 will be generally explained, with reference made to FIG. 1,FIG. 2, and FIG. 3. FIG. 1 is a block diagram of a electronic watch ofthe past.

FIG. 2 and FIG. 3 are waveform diagrams which show the rotationdetection operation of the load compensation of the electronic watchwhich is shown in FIG. 1, in which FIGS. 2 (a), (b), (c), and FIGS. 3(a), (b), and (c) are approximately the same as FIGS. 4, 5, 6, 7, 8, and9 in the Japanese Unexamined Patent Publication (KOKAI) No. 63-58192.

In FIG. 1, the normal watch section 200 corresponds to the FIG. 1 in theJapanese Unexamined Patent Publication (KOKAI) No. 63-58192, thisdrawing having been simplified for the purpose of the description.

In this drawing, the reference numeral 10 denotes a first steppingmotor, 13 is a first rotor which is a rotor of the first stepping motor10, 201 is an oscillator circuit, 202 is a frequencye divider circuit,203 is a normal drive pulse generation circuit, 204 is a compensationdrive pulse generation circuit, 205 is a coil switching pulse generationcircuit, 206 is a drive pulse supply means, 207 is a load compensationcontrol circuit, 208 is a coil switching pulse supply means, 209 is adrive circuit, and 210 is a detection circuit.

In this same drawing, 300 is a chronograph section, 20 is a secondstepping motor, 301 is a chronograph pulse generation circuit, 302 is achronograph pulse supply means, 303 is a second drive circuit, 116 is anS switch, and 117 is an R switch.

The normal watch section 200 will be described first. The oscillatorcircuit 201 outputs a 32768-Hz signal, based on the oscillation of aquartz crystal. The frequency divider circuit 202 divides the frequencyof this signal.

The normal drive pulse generation circuit 203 generates a normal drivepulse P1 as shown in FIG. 2 (b), based on a signal of the frequencydivider circuit 202.

The normal drive pulse P1 is a 5-ms pulse which has a ¼-ms pulse restingperiod in every 1 ms. The compensation drive pulse generation circuit204 generates a compensation drive pulse pH when it is judged that thefirst stepping motor 10 cannot rotate, as will be described later, basedon a signal of the frequency divider circuit 202.

The coil switching pulse generation circuit 205 generates the coilswitching pulses Pk1 through Pk13 such as shown in FIG. 2 (d), based ona signal of the frequency divider circuit 202. The coil switching pulsePk1 is output approximately 6 ms after the normal drive pulse P1, fromPk2 sequentially output. Each of the coil switching pulses Pk has apulse width of 0.125 ms.

The normal drive pulse P1 which is output by the normal drive pulsegeneration circuit 203 is supplied to the drive circuit 209 via thedrive pulse supply means 206.

Then pulses are alternately supplied to the first stepping motor 10 fromthe coil terminals O1 and O2, the first rotor 13 rotating, at which timethe current waveforms H3 and H4, shown in FIG. 2 (a) and FIG. 3 (a), aregenerated.

The current waveform H3 is the waveform when the first rotor 13 couldrotate, and the current waveform H4 is the waveform when the first rotor13 could not rotate.

The current waveforms H3 and H4, as shown by the current waveforms H3aand H4a, are considerable different current waveforms from the point intime after the normal drive pulse P1 is finished being output.

The detection of rotation and non-rotation conditions is judged bydetecting the difference in these current waveforms by detecting thedifference in the induced voltage when the coil switching pulse Pk isapplied to the drive circuit of the first stepping motor 10.

That is, as shown in FIG. 2 (d) and FIG. 3 (d), at an elapsed time of 6ms, at which point the rotation of the first rotor 13 has not completelyfinished, the coil switching pulse from the coil switching pulsegeneration circuit 205 is applied to the drive circuit 209 via the coilswitching pulse supply means 208.

It is then output to the first stepping motor 10 from the coil terminalO2.

The detection circuit 210 detects whether or not the induced voltage V1at this time exceeds the threshold voltage Vth. The load compensationcontrol circuit 207 receives the results of this detection, and in thecase in which the induced voltage V1 does not exceed the thresholdvoltage Vth, the next coil switching pulse Pk2 is output from the coilterminal O2.

If the induced voltage does not exceed the threshold voltage Vth, thisis repeated until the coil switching pulse Pk13 is output from the coilterminal O2.

If none of the induced voltages for all the coil switching pulses Pk1through Pk13 exceeds the threshold voltage Vth, the load compensationcontrol circuit 207 judges that the first stepping motor 10 did notrotate, and performs controls of the drive pulse supply means 206 so asto output a compensation drive pulse which is generated by thecompensation drive pulse generation circuit 204, thereby causing thefirst stepping motor 10 to rotate, via the drive circuit 209.

However, if one of the Pk coil switching pulses Pkn has an inducedvoltage Vn which exceeds the threshold voltage, the next coil switchingpulse Pkn+1 is switched so as to be output not from the coil terminalO2, but rather from the coil terminal O1.

Then once again the detection is performed by the detection circuit 210of whether or not the induced voltage of, for example, coil switchingpulses Pkn+1 through Pkn+6 exceed the threshold voltage Vth.

The load compensation control circuit 207 receives the results of thisdetection and, if even at least one of the induced voltages Vn+1 throughVn+6 of coil switching pulse Pkn+1 to Pknt+6, exceeded the thresholdvoltage, the judgment is made that the first stepping motor 10 hasrotated, and the load compensation control circuit 207 controls thedrive pulse supply means 206 so as not to output a compensation drivepulse Ph which is generated by the compensation drive pulse generationcircuit 204.

If, however, not evenone of the induced voltages Vn+1 through Vn+6,exceeded the threshold voltage, the judgment is made that the firststepping motor 10 did not rotate, the output of coil switching pulsesPkn+7 and thereafter being stopped, and the load compensation controlcircuit 207 performing control of the drive pulse supply means 206 sothat a compensation drive pulse which is generated by the compensationdrive pulse Ph generation circuit 204 is output to the first steppingmotor 10, thereby compensation for the delay caused by non-rotation.

The above-noted detection of rotation and non-rotation will next bedescribed in further detail. FIG. 2 (a) shows the current waveform H3occurring when the first stepping motor 10 rotates normally, and FIG. 2(b) and (c) show the voltages Vo1 and Vo2 occurring at this time at coilterminals O1 and O2.

FIG. 3 (a) shows the current waveform H4 which occurs when the firststepping motor load is heavy and it could not rotate, while FIGS. 3 (b)and (c) show the voltages Vo1 and Vo2 occurring at this time at coilterminals O1 and O2.

The detection of rotation of the first stepping motor 10 in FIG. 2 willnext be described. As shown in FIG. 3 (b), after a normal drive pulse P1is applied to the coil terminal O1, the coil switching pulse Pk1 isapplied to the coil terminal O2 at the detection time T1, the detectioncircuit 210 detecting whether or not the induced voltage V1 at that timeexceeds the threshold voltage Vth.

If at this time the current waveform H3 shown at FIG. 2 (a) is above thereference line G, the induced voltage V1 exceeds the threshold voltageVth, but if it is below the reference line G, the induced voltage doesnot exceed the threshold voltage Vth.

The position of the current waveform H3 at the detection time t1 is d1,and because this is below the reference line G, the induced voltage V1does not exceed the threshold voltage Vth. However, at detection timet2, the current waveform H3 is at the position d2, which is above thereference line G, this indicating that the induced voltage V2 exceedsthe threshold voltage Vth.

When the coil switching voltage Pkn is applied to the coil terminal O2,if the induced voltage Vn exceeds the threshold voltage Vth, the nextcoil switching pulse Pkn+1 is switched so as to be applied not to thecoil terminal O2, but rather to coil terminal O1. In this case, the coilswitching pulses are applied to the coil terminal O1 starting with thecoil switching pulse Pk3 output at the detection time t3.

In this case, in contrast to the case in which the coil switching pulseis applied to the coil terminal O2, if the current waveform H3 shown atFIG. 2 (a) is below the reference line G, the induced voltage V3 exceedsthe threshold voltage Vth, whereas if the current waveform H3 is abovethe reference line G, the induced voltage does not exceed the thresholdvoltage Vth.

At the detection time t3, the coil switching pulse Pk3 is output fromthe coil terminal O1, and because the position of the current waveformat that time is d3, which is above the reference line G, the inducedvoltage V3 does not exceed the threshold voltage Vth.

Further, at the detection times t4 and t5 as well, the current waveformH3 is at the positions, d4 and d5, respectively, these both being abovethe reference line G, indicating that the induced voltages V4 and V5 donot exceed the threshold voltage Vth.

However, at the next detection time, t6, the current waveform H3 is atthe position d6, which is below the reference line G, thereby indicatingthat the induced voltage V6 exceeds the threshold voltage Vth. At thesix coil switching pulses Pk3 through Pk8 which are applied to the coilterminal O1, if even one of the induced voltages V3-V8 exceeds thethreshold voltage Vth, the judgment is made that the first steppingmotor 10 rotated.

In this case, because the induced voltage V6 exceeds the thresholdvoltage, the judgment is made that the first stepping motor rotated, sothat the detection at coil switching pulses Pk7 and thereafter isstopped, and the compensation drive pulse Ph is not output.

Next, referring to FIG. 3, the rotation detection when the firststepping motor 10 did not rotate will be described. In this case,because the phase is 180 deg. different from the case of FIG. 2, anormal drive pulse P1 is applied to the coil terminal O2 as shown atFIG. 3 (b).

Then, the coil switching pulse Pk1 is applied to the coil terminal O1 atthe detection time t1, detection being made as to whether or not theinduced voltage V1 at that time exceeds the threshold voltage voltage.

In this case, similar to the case of FIG. 2 (a), if the current waveformH4 shown in FIG. 3 (a) is above the reference line G, the inducedvoltage V1 exceeds the threshold voltage Vth, and if it is below thereference line G, the induced voltage V1 does not exceed the thresholdvoltage Vth.

The position of the current waveform H4 at the detection time t1 is d1,which is below the reference line G, indicating that the induced voltageV1 does not exceed the threshold voltage Vth. Further, at the detectiontimes t2 and t3, the current waveform H4 positions are d2 and d3,respectively, these both being below the reference line G, indicatingthat the induced voltages V2 and v3 do not exceed the threshold voltageVth.

Then at the next detection time t4, the current waveform H4 position isd4, which is above the reference line G, indicating that the inducedvoltage V4 exceeds the threshold voltage Vth.

With the coil switching pulse Pk applied to the coil terminal O1, if theinduced voltage at that time exceeds the threshold voltage Vth, the nextcoil switching pulse Pkn+1 is switched so as to be applied not to thecoil terminal O1 but rather to the coil terminal O2. In this case, thecoil switching pulses starting with the coil switching pulse at thedetection time t5 will be applied to the coil terminal O2.

In this case, in contrast to the case in which the coil switching pulsesare applied to the coil terminal O1, if the current waveform H4 is belowthe reference line G in FIG. 3 (a) the induced voltage V5 exceeds thethreshold voltage Vth, and if it is above the reference line G theinduced voltage V5 doe snot exceed the threshold voltage Vth.

The position of the current waveform H4 at the detection time t5 is d5,which is above the reference line G, thereby indicating that the inducedvoltage V5 does not exceed the threshold voltage Vth. Further at thedetection times t6 through t10 as well, the current waveform H4 is atthe positions d6 through d10, respectively, these all being above thereference line G, indicating that the induced voltages V6 through V10 donot exceed the threshold voltage Vth.

The coil switching pulse Pk which is applied to the coil terminal O2 iscontrolled by a counter, so that if during a prescribed period of time(in this case the period between detection times t5 to t10) there is noteven one time of where the threshold voltage is exceeded, detection isstopped, a judgment is made that the first stepping motor did notrotate, 32 ms after which a compensation drive pulse Ph is output toperform compensation drive of the first stepping motor 10. By doingthis, the non-rotation condition is detected and load compensationoperation is performed so as to output a compensation drive pulse onlyin the case in which it is required.

In recent years, multifunction electronic watches have appeared whichhave, for example, a chronograph function (abbreviated as chronographfunction hereinafter) in addition to the normal time display. FIG. 4shows a plan view of an electronic watch module of the past having achronograph function, this electronic watch applying as well to thepresent invention.

In this drawing, the reference number 10 is the first stepping motorwhich is shown in FIG. 1, this comprising a first coil 11, a first yoke12, and a first rotor 13. The reference numeral 20 is the secondstepping motor which is shown in FIG. 1, this comprising a second coil21, a second yoke 22, and a second rotor 23. The numeral 4 denotes atime gear train, 5 is a second hand, 6 is a chronograph gear train, 7 isa functional hand including a chronograph hand, 116 is an S used tostart and stop the function including chronograph function, and 117 isan R switch used to reset function, for example, the function, forexample, and chronograph function.

The first stepping motor 10 rotates the first rotor 13, 180 deg. everyone second, thereby driving the second hand 5 via the time gear train,and further driving the hour hand, and the minute hand (not shown in thedrawing) to perform a normal display of the time.

The second stepping motor 20 performs a chronograph operation by meansof the S switch 116, rotating the second rotor 23 by 180 deg. in each 10ms by means of a high-speed 100-Hz pulse, thereby driving thechronograph hand 7 via the chronograph gear train 6 to perform afunctional display including chronograph display.

Next, the chronograph circuit operation will be described, withreference being made to FIG. 1 and FIG. 5. Since the normal watchsection 200 in FIG. 1 has already been described, this description willfocus on the chronograph section 300. FIG. 5 shows the pulse waveformsoutput by an electronic watch of the past.

A chronograph pulse generation circuit 301 generates the chronographpulse P11 as shown at FIG. 5 (b), based on a signal from the frequencydivider circuit 202. The chronograph pulse P11 is supplied from achronograph pulse supply means 302 to a second drive circuit 303 bymeans of a start operation of the S switch 116, output being madealternately from coil terminal O3 and O4 of the second drive circuit303, thereby driving the second stepping motor 20.

The normal drive pulse P1 which is applied to the coil terminal O1 ofthe above-noted first stepping motor 10 is a 5-ms pulse such as shown atFIG. 5 (a), this having a ¼-ms resting period each 1 ms. Rotation andnon-rotation are detected by the earlier-described method, and in thecase of non-rotation, as shown at FIG. 5 (a), a compensation drive pulsePh with a pulse width of 10 ms is output after 32 ms.

After one second, a normal drive pulse P1 is applied to the other coilterminal O2, this being alternately repeated. Next, the pulse which isapplied to the second stepping motor 20 will be described. With regardto the pulse which is applied to the second stepping motor 20, as shownin FIG. 5 (b), at the point at which the S switch is operated to startthe chronograph function a chronograph pulse P11 having a pulse width of4 ms is output from the coil terminal O3 of the second coil 21.

Then, after 10 ms, the chronograph pulse P11 is applied other coilterminal O4. These outputs are alternately repeated each 10 ms.

Although the above-noted first stepping motor 10 and the second steppingmotor 20 should be designed so as to be distant from one another toavoid interaction between their magnetic fields, because of a reductionin module size and the associated design requirements, there are casesin which the first stepping motor 10 and the second stepping motor 20are disposed as shown in FIG. 4, with just a small space D between them.

Thus, when one stepping motor rotates, it magnetically interferes withthe other stepping motor. In a motor such as the first stepping motor,in which detection is made of rotation and non-rotation, the above-notedmagnetic interference can result in a misjudgment that the firststepping motor has rotated, when in fact it has not rotated, therebyresulting in inhibiting of the output of the compensation drive pulse,this resulting in a disturbance of the timekeeping by the watch.

In particular in the case of a stepping motor such as the secondstepping motor which is rotating at a high speed of 1 Hz or higher,because pulses are constantly being output, the influence this motordrive has on the first stepping motor 10 in unavoidable. The mechanismof this erroneous detection will be described below.

FIG. 6 shows the waveforms which illustrate the rotation andnon-rotation detection in the load compensation operation of the past.FIG. 6 (a) the current waveform when a normal drive pulse P2 is appliedform the coil terminal O2 of the first stepping motor 10 for the case inwhich the first stepping motor 10 could not rotate. The solid linewaveform H1 is the current waveform when there is magnetic interferencefrom the second stepping motor 20 (that is, when the chronograph isoperating), while the dotted line wave form H2 is the current waveformwhen there is no magnetic interference therefrom (that is, when thechronograph is not operating).

FIG. 6 (b) shows the current waveform of the second stepping motor 20 atthat time. FIG. 6 (c) and FIG. 6 (d) show the voltage Vo2 at the coilterminal O2 of the first stepping motor 10 and the voltage Vo1 at thecoil terminal O1 of the first stepping motor 10, respectively.

FIG. 6 (e) shows the waveforms of the coil switching pulses Pk1 throughPk13.

The current waveform of the first stepping motor 10 is a waveform suchas shown as H2 in FIG. 6 (a) as long as the second stepping motor 20 isnot being driven. However, if the second stepping motor 20 is beingdriven, it creates magnetic interference as shown in FIG. 6 (b), thisresulting in the current waveform such as shown as H1 in FIG. 6 (a).

Turning now to what happens if detection of rotation and non-rotation isperformed under these conditions, first a normal drive pulse P1 isoutput from the coil terminal O2.

Then the coil switching pulse Pk1 is applied at the coil terminal O1 atthe detection time t1 and detection is made of whether or not theinduced voltage V1 at that time exceeds the threshold voltage Vth. If atthis time the waveform H1 is above the reference line G, the inducedvoltage V1 exceeds the threshold voltage, but if it is below thereference line G, it does not exceed the threshold voltage Vth.

The position of the current waveform H1 at the detection time t1 is d1,which is below the reference line G, indicating that the induced voltageV1 does not exceed the threshold voltage Vth. Additionally at detectiontimes t2 and t3 the current waveform H1 is at the positions d2 and d3,which are both below the reference line G, indicating that the inducedvoltages V2 and V3 do not exceed the threshold voltage Vth. At the nextdetection time t4, the current waveform H1 position is d4, which isabove the reference line G, thereby indicating that the induced voltageV4 exceeds the threshold voltage Vth.

With the coil switching pulse Pkn applied to the coil terminal O1, ifthe induced voltage at this time exceeds the threshold voltage Vth, thenext coil switching pulse Pkn+1 is switch so as to be applied not to thecoil terminal O1, but rather to the coil terminal O2. That is, the coilswitching pulses Pk5 starting from the coil switching pulse Pk5 atdetection time t5 are applied to the coil terminal O2.

In this case, in contrast to the case in which coil switching pulses areapplied to the coil terminal O1, if the current waveform is below thereference line G, the induced voltage at that time exceeds the thresholdvoltage Vth, but if the current waveform is above the reference line G,the induced voltage does not exceed the threshold voltage Vth.

With regard to the coil switching pulse Pk5 which is now applied to thecoil terminal O2 at the detection time t5, because of the influence ofmagnetic interference, the current waveform position H1 is d5, whereasit should normally have been at d′5. For this reason, although withoutthe magnetic interference the position of the current waveform H2 wouldhave been above the reference line G at d′5, indicating that the inducedvoltage V5 did not exceed the threshold voltage Vth, the effect of themagnetic interference is to move the position of the current waveform H1at the d5, which is below the reference line G, indicating that theinduced voltage V5 exceeds the threshold voltage Vth.

If the any one of the induced voltages V5 through V10 for the coilswitching pulses Pk5 through Pk10 exceeds the threshold voltage Vth, thejudgment is made that the stepping motor was driven.

Thus, although the first stepping motor has not actually rotated, anerroneous detection to the effect that it did not rotate occurs, and acompensation drive pulse Ph is not output as a result. Therefore, theaction of the above-noted compensation drive pulse Ph in compensatingthe first stepping motor does not occur, and the time kept by this motorlags.

In addition, in the past there has been a commercially producedelectronic watch which used a solar cell on the clock face, this beingused in combination with a storage means such as an electricaldouble-layer capacitor or the like, rather than a battery (thiselectronic watch being referred to hereinafter as a solar watch).

Because the output voltage of an electrical double-layer capacitor isnot constant, the stepping motor drive method in the solar watch wasthat of making a plurality of normal pulses available, these havingdiffering driving forces. Additionally a means for detecting rotationand non-rotation was provided, a normal drive pulse being selected andoutput from the plurality of normal drive pulses which would enabledrive with the minimum current a the voltage present at that time,thereby driving the stepping motor in a manner that accommodated thevarying voltage.

The solar watch of the past will be described, with reference being madeto FIG. 7. FIG. 7 shows the block diagram of the solar watch of thepast, and FIG. 8 shows the waveforms of the normal pulse Ps of the solarwatch which is shown in FIG. 7. In FIG. 7, the reference numeral 45denotes a solar cell which generates electricity in response to light,70 is an electrical double-layer capacitor which stores electricalenergy, 10 is a first stepping motor, 150 is a watch circuit whichoperates by the electrical power which is stored in the electricaldouble-layer capacitor 70, 101 is an oscillator circuit which generatesthe reference clock required for circuit operation, 102 is a frequencydivider circuit which divides the frequency of the reference clockgenerated by the oscillator circuit 101, 103 is a first normal pulsegeneration circuit which generates the normal pulses Ps1 through Ps8 forthe purpose of normal drive of the first stepping motor 10 and acompensation drive pulse Psh for the purpose of performing compensatingdrive, 108 is a first normal pulse selection circuit which selects onemoral pulse Ps from the normal pulses Ps1 through Ps8 which aregenerated by the first normal pulse generation circuit, 133 is a clockcontrol circuit which performs timekeeping based on a signal from thefrequency dividing circuit 102, 120 is a first drive circuit for thepurpose of driving the first stepping motor 10, 115 is a second handcontrol circuit which is controlled by the clock control circuit 122,and which supplies the normal pulse signal Ps which is selected by thefirst normal pulse selection circuit 108 to the first drive circuit 120each one second, 119 is a first detection circuit which detects therotation and non-rotation of the first stepping motor, and 114 is afirst load compensation control circuit which performs control of thefirst normal pulse selection circuit 108 based on the results of thejudgment made by the first detection circuit 119.

Next, circuit operation will be described.

The electrical energy generated by the solar cell 45 is stored in theelectrical double-layer capacitor 70. The watch circuit 150 uses theelectrical double-layer capacitor 70 as its power supply, and is drivenby the power supply voltage Vc.

The first normal pulse generation circuit 103 generates the normalpulses Ps1 through Ps8 and the compensation pulse Psh, based on a signalfrom the frequency divider circuit 102. The first normal pulse selectioncircuit 108 is controlled by the first load compensation control circuit114, selects one normal pulse Ps from the normal pulses Ps1 through Ps8,according to a method to be described later, supplying this to thesecond hand control circuit 115 and transfers the magnitude of thecurrently selected normal pulse Ps to the first load compensationcontrol circuit 114 by means of the signal S.

The second hand control circuit 115 supplies the normal pulse Ps to thefirst drive circuit 120 each one second, in accordance with the timethat is kept by the watch control circuit 133. The first drive circuit120 drives the first stepping motor 10 by means of the normal pulse Ps.The first load compensation control circuit 114 controls the firstnormal pulse selection circuit 108 by means of the results of thejudgment of the first detection circuit 119, and in the case in whichrotation was detected, outputs the same normal pulse Ps next time, butin the case in which non-rotation is detected, outputs the compensationdrive pulse Psh and switches the next normal pulse Ps to the next largernormal pulse Ps.

Next, the pulse shapes will be described, FIGS. 8 (a) through (c) showsthe waveforms of the normal pulses Ps1, Ps4, and Ps8 of the normalpulses Ps1 through Ps8 which are available. The normal pulses Ps1through Ps8 have a pulse width of 4 ms, but each have a pulse restingperiod that differs by 0.05 ms each. The normal pulse Ps1, as shown inFIG. 8 (a), has a pulse resting period Ks1 of 0.35 ms every 1 ms, thenormal pulse Ps4 has a pulse resting period Ks4 of 0.2 ms every 1 ms,and the normal pulse Ps8 has no pulse resting period.

Although it is not shown in the drawing, the normal pulses Ps2, Ps3,Ps5, Ps6, and Ps7 have pulse resting periods of 0.3 ms, 0.25 ms, 0.15ms, 0.1 ms and 0.05 ms, respective, every 1 ms. FIG. 8 (d) shows thecompensation drive pulse Psh which is output when the judgment is madethat drive was not possible by the normal pulse Ps.

The compensation drive pulse Psh is output 32 ms after the normal pulsePs, has a pulse width of 12 ms and has 0.5-ms pulse resting periodsevery 1 ms in the latter 6 ms of this 12 ms.

TABLE 1 Normal Pulse Ps Pulse Resting Periods and Minimum Drive VoltagesNormal Pulse Pulse Resting Period Minimum Drive Voltage Ps1 0.35 ms 2.6VPs2 0.3 ms 2.3 VPs3 0.25 ms 2.0 VPs4 0.2 ms 1.8 VPs5 0.15 ms 1.6 VPs60.1 ms 1.4 VPs7 0.05 ms 1.2 VPs9 (None) 1.0 V

As described above, because the normal pulses Ps1 through Ps8 havemutually differing pulse resting periods, the associated minimumvoltage, that is, the minimum drive voltage is different for each. Table1 shows the pulse resting periods and minimum drive voltages for each ofthe normal pulses Ps.

Because the normal pulse Ps8 has no resting period, it has the largestdriving capacity, so that drive is possible even if Vc is only 1.0 V.The normal pulse Ps 1 has a long resting period of 0.35 ms, and thus hasthe smallest driving capacity. Thus, at a low voltage at which drive isnot possible, drive is only possible at a power supply voltage Vc of 2.6V or greater.

However, at a high power supply voltage Vc, the normal pulse Ps8 hasmore drive capacity than is necessary, so that the power consumptionbecomes large. In contrast to this, the normal pulse Ps1 enables driveat a power supply voltage Vc of 2.6 V or greater with a powerconsumption that is lower than any of the normal pulses Ps2 through Ps8.The normal pulses Ps2 through Ps7 each have the minimum drive voltagescorresponding to their respective pulse resting periods. The solar watchis driven by the most optimal normal pulse Ps that has a low powerconsumption with respect to the power supply voltage of the electricaldouble-layer capacitor 70.

Next, the method of selecting an optimal normal pulse Ps will bedescribed. In the load compensation control method practiced in thepast, a given normal pulse Ps(n) is output, and if drive was notpossible the next output normal pulse is selected as the next largernormal pulse Ps(n+1). If rotation occurred, however, the next pulse isthe same normal pulse Ps(n), this being output a prescribed number oftimes, for example 100 times continuously, after which the next pulsewas the next smaller normal pulse Ps(n−1).

By performing the above-noted operation, it is possible to select theoptimum normal pulse. Take, for example, the case in which the powersupply voltage Vc of 1.7 V, and in which the normal pulse Ps3 is output.From Table 1, it can be seen that, with a power supply voltage Vc of1.7, the smallest normal pulse usable for drive is the normal pulse Ps5,with which drive is possible with a minimum voltage of 1.6 V, making thenormal pulse Ps5 the optimum pulse when the power supply voltage Vc is1.7 V.

Since the minimum drive voltage with the normal pulse Ps3 pulse is 2.0V, drive is not possible with a power supply voltage Vc of 1.7 V. Thus,the first stepping motor 10 cannot be rotated, and the first detectioncircuit 119 makes the judgment that rotation was not possible. Inaccordance with the results of this judgment, the first loadcompensation control circuit 114 controls the first normal pulseselection circuit 108 so as to output a compensation drive pulse Psh,and also makes a switch to the next larger normal pulse Ps4 starting atthe next time.

Thus, the first stepping motor 10 drive is compensated reliably by thecompensation drive pulse Psh, and the next larger normal pulse Ps1 isoutput the next time. Note, however, that from Table 1 it can be seenthat because the minimum drive voltage with the normal pulse Ps4 is 1.8V, it still is not possible to perform drive with the power supplyvoltage Vc of 1.7 V. Therefore, it is not possible for the firststepping motor 10 to rotate, and the first detection circuit 119 makesthe judgment that rotation was not possible.

In accordance with the results of this judgment, the first loadcompensation control circuit 114 controls the first normal pulseselection circuit so as to output a compensation pulse Psh and alsomakes a switch to the next larger normal pulse Ps5 starting the nexttime. Thus, the drive of the first stepping motor 10 is reliablycompensated once again, and the next larger normal pulse Ps5 is outputthe next time. With the normal pulse Ps5 the minimum drive voltage is1.6, so drive is possible with the power supply voltage Vc of 1.7 V.

Therefore, the first detection circuit 119 makes the judgment thatrotation was possible. In accordance with the results of this judgment,the first load compensation control circuit 114 controls the firstnormal pulse selection circuit 108 so that a compensation drive pulsePsh is not output, and outputs the same normal pulse Ps5 the next timeas well. Thus, the normal pulse Ps5 is output the next time as thenormal pulse Ps. Furthermore, if the power supply voltage Vc continuesto be 1.7 V, when the normal pulse Ps5 is output continuously for 100times, the first load compensation control circuit 114 controls thefirst normal pulse selection circuit 108 so as to output the nextsmaller normal pulse Ps4 as the next normal pulse Ps.

However, because with the normal pulse Ps4 drive is not possible withthe power supply voltage Vc of 1.7 V, the compensation pulse Psh isoutput to perform compensation drive, the normal pulse being returned tothe next larger normal pulse Ps5 the next time output is made. In theabove-described manner, with a power supply voltage Vc of 1.7 only onetime out of 100 times is the normal pulse Ps4 output and drive notpossible, so that the compensation pulse Psh is output to perform drivecompensation, and at the other times drive continues with the optimumnormal pulse Ps5. Although the current consumption of the compensationpulse Psh is larger than with a normal pulse Ps, this occurs only onetime in 100, so that th effect extremely small and not enough to cause aproblem.

Next, the case in which the power supply voltage Vc increases from 1.7 Vto 2.1 V will be described. From Table 1, with a power supply voltage of2.1 V, the optimum normal pulse Ps is the normal pulse Ps3, which has aminimum drive voltage of 2.0 V, the drive capacity with the normal pulsePs5 being excessively large, so that the current consumption becomeslarger than necessary. Note that, as described above, out of each 100outputs of the normal pulse Ps5, the normal pulse Ps4 is output onetime.

The minimum drive voltage with the normal pulse Ps4 is 1.8 V and whiledrive was not possible with a power supply voltage Vc of 1.7 V, drive ispossible at a power supply voltage Vc of 2.1 V. Thus, when the normalpulse Ps4 is output, if the power supply voltage Vc is 2.1 V, the firststepping motor 10 is driven by this normal pulse Ps4, and the firstdetection circuit 119 makes the judgment that rotation was possible.

In accordance with the results of this judgment, the first loadcompensation control circuit 114 controls the first normal pulseselection circuit 108 so that a compensation pulse Psh is not output,and so that the same normal pulse Ps4 is selected for output next timeas well. Then, the next time as well, the normal pulse Ps4 is output asthe normal pulse Ps.

In addition, when the normal pulse Ps4 is output 100 times, the firstload compensation circuit 114 controls the first normal pulse selectioncircuit 108 so that the next smaller normal pulse Ps3 is selected foroutput the next time. Because the minimum drive voltage with the normalpulse Ps3 is 2.0 V, so that drive is possible with a power supplyvoltage Vc of 2.1 V as well, the next time the same normal pulse Ps3 isoutput the next time as well.

By performing the above-noted operation, the normal pulse Ps3, which isthe optimum normal pulse when the power supply voltage Vc is 2.1 V, isselected and output. Furthermore, after the normal pulse Ps3 is output100 times, the next smaller normal pulse Ps2 is output, but drive is notpossible at a power supply voltage Vc of 2.1 with this normal pulse Ps2,so that after the compensation pulse Psh performs compensation drive,the output normal pulse Ps is returned once again to the normal pulsePs3. By doing this, it is possible to select and output the normal pulsewhich is optimum for a varying power supply voltage Vc.

This operation operates not only with respect to the power supplyvoltage variations, but with respect to the drive load of the calendarand the like, enabling the selection of the output of the optimum normalpulse at all times. The above-noted operation will be referred tohereinafter as multistage load compensation operation.

In recent years there has arisen demands from electronic watches for notonly the normal time display, but for various additional functions suchas an alarm function and a chronograph function. Specifically, in thecase of an analog-indicating electronic watch, there is a desire to beable to do such things as switch from the normal time display to thealarm time display, and to perform operations such as fast-forward andfast-reverse with the chronograph display, which require drivecapability by means of a non-normal pulse, and these desires haveoccurred with solar watches as well.

However, it is known that with a solar watch the power supply voltagevaries widely, making it impossible to obtain sufficient motor driveenergy with a fixed pulse width when performing non-normal pulse drivesuch as high-speed pulse drive and reverse pulse drive at low voltages,another associated problem being that a high voltages rotor overrunoccurs, preventing proper drive, and thereby limiting the voltage rangeover which drive is possible. Accommodation of the above-noted functionsin solar watches, in which the power supply voltage varies widely, istherefore not possible.

An effective drive means when the voltage is varying is theabove-described multistage load compensation operation, and it can beenvisioned that this method can be used to perform high-speed rotationand reverse rotation. However, with multistage load compensation,because of the time period for detection an the time period of output ofa compensation drive pulse, the amount of time until the output of thenext pulse becomes long, this posing the problem of preventinghigh-speed drive. For example, even if the pulse width of the normalpulse is as short as 4 ms, there is an addition detection time period ofapproximately 20 ms, and if rotation was not possible a compensationdrive pulse having a width of 12 ms is output from the 32 ms point.

Therefore, during the amount of time until the drive is completed with acompensation drive pulse, that is, during the 50-ms period of time whichis the total of the 32 ms before output of the compensation drive pulse,the 12-ms pulse width of the compensation drive pulse, and thestabilization time of approximately 8 ms, it is not possible to outputthe next normal pulse.

Therefore, with multistage load compensation, it is not possible toperform drive with a pulse interval of smaller than 50 ms. That is,drive at a frequency of higher than 20 Hz is not possible. Thus, insolar watches in the past it was difficult to perform high-speedrotation or reverse rotation. One method of solving the above-describedproblem is to detect the power supply voltage, and to output high-speedpulse or reverse pulse having a width responsive to the voltage at thattime. An example of detecting the voltage and changing the width of areversing pulse was proposed as an electronic watch stepping motor inthe Japanese Unexamined Patent Application S55-59375.

However when performing high-speed rotation or reverse rotation in asolar watch, in which the voltage varies over a wide ranges such as fromapproximately 1 V to 3 V, it is necessary to perform a plurality ofvoltage detections corresponding to the drive voltage ranges for thesepulses. For example, if a high-speed pulse or reversing pulse is to beoutput to correspond to each of the four divided voltage ranges of 1 to13 V, 1.3 to 1.7 V, 1.7 to 2.3 V, and 2.3 to 3 V, it is necessary toperform voltage detection at the five voltages of 1 V, 1.3 V, 1.7 V, 2.3V, and 3 V.

Furthermore, if the variations between components being used andenvironmental conditions such as the operating temperature areconsidered, reliable operation requires that the voltage detection beperformed with considerable accuracy. It is extremely difficult toperform high-accuracy voltage detection within such as small system asan electronic watch.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an electronic watchwhich offers an improvement with respect to the above-noted drawback inthe prior art, this electronic watch either comprising a drive motorwhich is driven by a normal hand-drive pulse and a drive motor which isdriven by a non-normal hand-drive pulse, or comprising a single drivemotor which is driven by normal hand-drive pulse and a non-normalhand-drive pulse, and being capable not only of maintaining accuracytimekeeping display or functional display including chronograph display,but also of achieving low power consumption.

More specifically, the first object of the present invention is toprovide an electronic watch in which, when an external operating elementis operated, at a voltage lower than a prescribed voltage thereverse-rotation derive of the above-noted drive motor is disabled andalso in which the above-noted drive motor is driven in the forwarddirection by a pulse of a low drive frequency over a wide frequencyrange.

The second object of the present invention is to provide an electronicwatch in which there exist at least two drive motors adjacent to oneanother, and which has a function that prevents erroneous detection inthe load compensation operation of one drive motor caused by magneticinterference thereto from the other drive motor.

A third object of the present invention is to provide an electronicwatch in the case in which a power supply having a varying outputvoltage is used, this electronic watch having finctions including analarm function or a chronograph function which enables high-speedrotation or reverse rotation of the drive motor by a non-normalhand-drive pulse which is either a high-speed pulse or a reverse-drivepulse, even when the output voltage of the power supply varies, withoutdetecting the voltage of the power supply.

To achieve the above-noted objects, the present invention makes use ofthe basic technical constitution which is described below. Specifically,it is an electronic watch which comprises a power supply, an oscillatorcircuit, a drive pulse generating means, a drive motor which minimallydrives one hand of the hour/minute, second, and finctional handsincluding chronograph hands in response to a drive pulse which is outputby the above-noted drive pulse generating means, a drive circuit meanswhich controls the drive of the above-noted drive motor, a drive circuitcontrol means which controls the above-noted drive circuit means, and acontrol condition detection means which is connected to the above-noteddrive circuit control means and which detects the control detectionmeans being provided with a non-proper condition detection means whichsenses the occurrence of a condition in which it is not possible toproperly drive the above-noted drive motor under a prescribed conditionin a prescribed control mode currently being executed, and a controlmode change-instructing means which, in response to a detection signalof the above-noted non-proper condition detection means, issues aninstruction to the drive circuit control means to change the controlmode currently being executed.

That is, in an electronic watch according to the present invention insupplying a prescribed drive pulse to an appropriate drive motor via thedrive circuit control means so as to cause the execution by theabove-noted drive motor of a prescribed display operation, in additionto monitoring the control mode which is currently being executed by thedrive circuit control means, in the case in which, in this control mode,because of a change in the drive voltage of the power supply or a changein another condition, a condition occurs in which the reliability withregard to a prescribed display operation of the drive motor decreases,the control mode is changed either by causing the above-noted drivecircuit control means to stop the currently executing control mode, orcausing it to execute a different control mode, or by performingprocessing, for example, to change the output condition of the drivepulse, so that regardless of the manner in which the drive environmentchanges, it is not only possible to maintain a proper drive condition inthe above-noted drive motor, but also to drive the above-noted drivemotor at all times with an optimum low power consumption, therebyenabling the achievement of operation with low power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an embodiment of an electronic watch in thepast.

FIGS. 2A-2D are waveform diagrams which show the operation of rotationdetection for load compensation in the past.

FIGS. 3A-3D are form diagrams which show the operation of non-rotationdetection for load compensation in the past.

FIG. 4 is a plan view of an electronic watch module of the past.

FIGS. 5A and 5B are diagrams which show the pulse waveforms output in anelectronic watch of the past.

FIGS. 6A-6E are waveform diagrams which show the rotation detectionoperation for load compensation in the past.

FIG. 7 is a block diagram which shows an example of the configuration ofa solar watch in the past.

FIGS. 8A-8D are waveform diagrams which show the normal pulses Ps1through Ps8 in the past.

FIG. 9 is a block diagram which shows the basic configuration of anelectronic watch according to the present invention.

FIG. 10 is a circuit block diagram which shows the first aspect of anembodiment of an electronic watch according to the present invention.

FIGS. 11A-11E are output waveform diagrams which show the waveforms ofthe main part of the circuit block diagram shown in FIG. 10.

FIG. 12 is an outer view of an electronic watch which shows anembodiment of the present invention.

FIG. 13 is a block diagram which shows the second aspect of anembodiment of an electronic watch according to the present invention.

FIGS. 14A-14D are waveform diagrams which show the output pulsewaveforms in the second aspect of an embodiment of an electronic watchaccording to the present invention.

FIG. 15 is a block diagram which shows the third aspect of an embodimentof an electronic watch according to the present invention.

FIG. 16 is a plan view of the construction of an electronic watch of theabove-noted embodiment of the present invention.

FIG. 17 is a waveform diagram of the reverse pulse Pb of an embodimentof the present invention.

FIG. 18 is a block diagram which shows the area surrounding the firstload compensation circuit of an aspect of embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Examples of an electronic watch according to the present invention willbe described in detail below, with reference being made to theappropriate accompanying drawings.

FIG. 9 is a block diagram which shows in simplified form an example ofthe configuration of an electronic watch 400 according to the presentinvention. In this drawing, the electronic watch comprises a powersupply 401 and a watch circuit 402. The watch circuit 402 comprises anoscillator circuit 403, a frequency divider circuit 404, a drive pulsegeneration means 405, a drive motor 406 which, in response to a drivepulse P1 that is output by the above-noted drive pulse generation means405, drives at least one of the hour/minute, second, and functionalhands including chronograph hands, a drive circuit means 407 whichcontrols the drive of the drive motor 406, a drive circuit control means408 which controls the above-noted drive circuit means 407, and acontrol condition detection means 409 which is connected to theabove-noted drive circuit control means 408 and which detects thecontrol condition in the drive circuit control means 408, the controlcondition detection means 409 being provided with a non-proper conditiondetection means 410 which senses the occurrence of a condition in whichit is not possible to properly drive the above-noted drive motor 406under a prescribed condition in a prescribed control mode currentlybeing executed, and a control mode change-instructing means 411 which,in response to a detection signal of the above-noted non-propercondition detection means 410, issues an instruction to the drivecircuit control means 408 to change the control mode currently beingexecuted.

In the electronic watch 400 according to the present invention, there anbe one above-noted drive motor 406, in which case it is possible to makeboth timekeeping display and for example, chronograph display using asingle drive motor 406, and it is also possible to make the timekeepingdisplay and the chronograph display using separate drive motors, byminimally have the two drive motor 406-1 and 406-3. Additionally, it ispossible to have two drive motors 406-1 and 406-2 for the timekeepingdisplay, and to have a single drive motor 406-3 for the chronographdisplay.

Thus, in the case of using a plurality of motors, it is desirable tohave a number of drive circuit means 407 which corresponds to the numberof drive motors.

While no specific limitation is imposed with regard to the power supplyused in the electronic watch 400 according to the present invention, itis particularly effective in the case of a power supply having aconfiguration which exhibits variation in voltage during timekeepingdisplay operation or a power supply such as titanium-lithium batteries,solar batteries, i.e., secondary batteries and condensers having largecapacitance rechargeable batteries and the like, which have aconfiguration which exhibits up and down fluctuations of voltage duringtimekeeping display operation.

Additionally there is no particular limitation imposed with regard tothe constitution of the oscillation means 404 and frequency dividingmeans 405 used in the present invention, it being possible to use aknown oscillation means and a know frequency dividing means of the past.

In addition, it is desirable that the drive pulse generation means 405used in the electronic watch 400 according to the present invention, inaddition to including a normal hand-drive pulse generation circuit 405-awhich generates drive pulse for normal hand drive from a pulse having aprescribed frequency, via the frequency divider circuit 404, from theoscillation of the oscillator circuit 403, also includes at least onepulse generation circuit selected from, for example, a compensationdrive pulse generation circuit 405-b, a drive motor rotation detectionsignal pulse generation circuit 405-c, a low-voltage hand-drive pulsegeneration circuit 405-d, a fast-forward (high-speed) pulse generationcircuit 405-e, a low-voltage fast-forward pulse generation circuit405-f, a reverse-rotation pulse generation circuit 405-g, and afunctional hand drive pulse generatint circuit for example, achronograph hand-drive high-speed rotation pulse generation circuit405-h.

Furthermore, of the above-noted pulse generation circuits used in theabove-noted electronic watch 400 of the present invention it is possibleto have a configuration in which one drive pulse is output from at leastone pulse generation circuit selected from the normal hand-drive pulsegeneration circuit 405-a, the fast-forward (high-speed) pulse generationcircuit 405-e, the reverse-rotation pulse generation circuit 405-g, andthe functional hand drive pulse generating circuit, for example, thechronograph hand-drive high-speed rotation pulse generation circuit405-h, and it is also further more desirable to have a configurationwhich a plurality of drive pulses having mutually differing drivecapacities are output.

In addition, the compensation drive pulse generation circuit 405-b usedin the electronic watch 400 according to the present invention is acircuit which generates a compensation drive pulse Ph that it used inthe case, as described earlier, load compensation is to be performed,and while this compensation drive pulse generation circuit 405-b can beconfigured, similar to the other above-noted group of pulse generationcircuits, as an independent circuit as shown in FIG. 9, it is alsopossible to have this compensation drive pulse generation circuit 405-bprovided within a single pulse generation circuit selected from theabove-noted the normal hand-drive pulse generation circuit 405-a, thefast-forward (high-speed) pulse generation circuit 405-e, thereverse-rotation pulse generation circuit 405-g, and the chronographhand-drive high-speed rotation pulse generation circuit 405-h.

Furthermore, the drive circuit control means 408 which is used in theelectronic watch 400 according to the present invention includes a loadcompensation control system 412 which detects whether or not theabove-noted drive motor 406 rotated in response to the prescribed drivepulse P1 which as supplied by the above-noted drive circuit means 407and, in the case in which the judgment is made that the drive motor 406did not rotate, supplies a described compensation drive pulse Ph to thedrive circuit means 407.

The control condition detection means 409 used in the electronic watch400 according to the present invention is connected to the drive circuitcontrol means 408, and it is desirable that this control conditiondetection means 409 further has an non-proper condition detection means410 comprising preferably at least one means selected from the means fordetecting the voltage level of the power supply or means for detectionthe drive condition of the driver motor other than the drive motor whichis executing the prescribed drive control, and means for detecting thepredicted voltage level of the power supply which is sensed by theabove-noted load compensation control system 412.

The control mode change-instructing means 411 which is used in thecontrol condition detection means of the present invention is configuredso as to have at least one method of instruction a change in response toa detection signal from the above-noted non-proper condition detectionmeans 410, this being either output to the above-noted drive circuitcontrol means of an instruction to stop the control mode current beingexecuted, output to the drive circuit control means of an instruction tochange from the currently executed control mode to a different controlmode, or output to the drive circuit control means of an instruction tochange from the prescribed drive pulse being used in the control modecurrently being executed to a different drive pulse.

The configuration of the electronic watch 400 according to the presentinvention will be described in detail below, making reference to theaccompanying drawings with regard to the aspects thereof.

FIG. 10 is a block diagram which shows a specific example of theconfiguration of the first aspect of the electronic watch 400 accordingto the present invention, this electronic watch 400 comprising the powersupply 401 and the watch circuit 402. The watch circuit 402 comprises anoscillator circuit 403, a frequency divider circuit 404, a drive pulsegeneration means 405, a drive motor 406 which, in response to a drivepulse P1 that is output by the above-noted drive pulse generation means405, drives at least one of the hour/minute, second, and chronographhands, a drive circuit means 407 which controls the drive of the drivemotor 406, a drive circuit control means 408 which controls theabove-noted drive circuit means 407, and a control condition detectionmeans 409 which is connected to the above-noted drive circuit controlmeans 408 and which detects the control condition in the drive circuitcontrol means 408, the above-noted drive pulse generation means 405including at least a normal hand-drive pulse generation circuit 405-a, afast-forward (high-speed) pulse generation circuit 405-e which generatesa fast-forward pulse in response to an operation of an externaloperating element, and a reverse-rotation pulse generation circuit 405-gwhich generates a reverse-rotation pulse in response to an operation ofan external operating element, and additionally the above-noted controlcondition detection means 409 is provided with a non-proper conditiondetection means 410 comprising a voltage level discrimination means410-a which detects the voltage level of the power supply 401, and acontrol mode-changing instruction circuit 411 comprising a selectionmeans 411-1 which, in response to an output signal from the above-notednon-proper condition detection means 410, selectively causes the driveoutput signals of each of the pulse generation circuit 405 to pass,wherein in the case in which the power supply voltage is outside aprescribed voltage range, in response to a discrimination signal outputfrom the non-proper condition detection means 410, the controlmode-changing instruction circuit 411 prohibits the drive circuitcontrol means 408 from passing a reverse-rotation pulse.

Additionally, as another specific example of the electronic watchaccording to the present invention, in the above-noted configuration thedrive pulse generation means is provided with a low-voltage fast-forwardpulse generation circuit which generates a fast-forward pulse for use ata low voltage, this being a drive pulse having a width that is widerthan the fast-forward pulse, the configuration being such that in thecase in which the power supply voltage has gone outside of a prescribedvoltage range, in response to a discrimination signal output from theabove-noted non-proper condition detection means, the controlmode-changing instruction circuit permits the drive circuit controlmeans to pass the low-voltage fast-forward pulse.

The electronic watch 400 in the above-noted first aspect of the presentinvention will next be described in further detail.

Specifically, the electronic watch 400 of the above-noted first aspectof the present invention, which has a hand-drive pulse generationcircuit 405-a that generates a normal hand-drive pulse, a fast-forwardpulse generation circuit 405-e that generates a fast-forward pulse inresponse to an operation of an external operating element, areverse-rotation pulse generation circuit 405-e that generates areverse-rotation pulse in response to an operation of an externaloperating element, and a stepping motor which performs each of theoperations of normal rotation, fast-forward rotation, and reverserotation, in response to the above-noted pulses, is provided with avoltage level discrimination circuit 410-1 that discriminates the levelof the power supply voltage, and with a control circuit 411-1 which iscontrolled by an output signal of the voltage level discriminationcircuit 410-1 and which causes selective passage of an output signalfrom the above-noted pulse generation circuits, wherein if the powersupply voltage falls below the prescribed voltage range so that alow-voltage discrimination signal is generated from the above-notedvoltage level discrimination circuit 410-1, the passage of theabove-noted control circuit 411-1 prohibits the passage of thereverse-rotation pulse.

Next, an embodiment of the present invention will be described inrelation to FIG. 10 in terms of the stepping motor fast-forwardoperation and reverse-rotation operation when correcting the timesetting in a solar cell watch advancing a second hand every second.

In FIG. 10, the reference numeral 403 denotes an oscillator circuit and404 denotes a frequency divider circuit, whereby the output of theoscillator circuit 403 is frequency divided by the frequency dividercircuit 404 to obtain the signals required for the operation of thewatch.

In this drawing, 405-a is a hand-drive pulse generation circuitgenerates a pulse for normal hand drive, this outputting a hand-drivepulse having a width of 5 ms every 1 second, as shown in FIG. 11 (a),during normal hand drive. The reference numeral 405-d denotes alow-voltage hand-drive pulse generation circuit, which outputs ahand-drive pulse comprising two pulses having a width of 6 ms every 2seconds, as shown in FIG. 11 (b). Furthermore, although it iscommonplace technology at present, if detection is performed of rotationand non-rotation of the rotor 422 after being driven by a hand-drivepulse and a compensation drive pulse having a wide pulse width is outputfrom the hand-drive pulse generation circuit 405-a when non-rotation isdetected, this low-voltage hand-drive pulse generation circuit 405-d isnot absolutely necessary. The reference numeral 405-e denotes afast-forward pulse generation circuit, and if the external operatingelement 34 shown in FIG. 12 and to be described later is continuouslypressed, fast-forward pulses having a pulse width of 4 ms are output ata rate of 64 per second, as shown in FIG. 11 (c).

The reason the pulse width is made narrower than the normal hand-drivepulse is to increase the drive frequency. However, because the pulsewidth is narrow, it is difficult to drive the stepping motor with a lowvoltage. The reference numeral 405-5 denotes a low-voltage fast-forwardpulse generation circuit, which outputs fast-forward pulses having apulse width of 6 ms at a rate of 32 each one second, as shown in FIG. 11(d), when the external operating element 34, shown in FIG. 12 and to bedescribed later, is continuously pressed. The drive frequency isproportionally one half of the output of the fast-forward pulsegeneration circuit 405-e, and the pulse width thereof is wide.Therefore, even at a low voltage at which drive by the output signal ofthe fast-forward pulse generation circuit 405-e is not possible, it ispossible to normally drive the stepping motor. The reference numeral405-g denotes a reverse-rotation pulse generation circuit, which outputsgroups of three pulses, these being output at a rate of 32 groups in aperiod of one second, as shown in FIG. 11 (e), when the externaloperating element 35, shown in FIG. 12 and to be described later, iscontinuously pressed.

The reference numeral 458 denotes a solar cell which converts lightenergy to electrical energy, with a capacitor or secondary cell used asthe power supply. The reference numeral 410-1 denotes a voltage leveldiscrimination circuit which outputs a high signal when the power supplyvoltage is, for example, 1.2 V or greater, and which outputs a lowsignal when the power supply voltage is below, for example, 1.2 V.

This power supply voltage discrimination circuit 410-1 forces current toflow when the power supply voltage is 1.8 V or greater, and isconfigured so as to prevent the power supply voltage from reaching orexceeding 1.8 V.

The reference numeral 408 denotes a control circuit which comprises acontrol mode-changing instruction means 411-1 formed by the AND gates451 through 455 and the OR gate 456 which, in response to an outputsignal of a voltage level discriminating circuit 410-1, which is anon-proper condition detection means 410 to be described later, switchthe output drive pulse, and which further comprises the toggle-typeflip-flop 417, and the AND gates 418 and 419.

The AND gate 451 has the output signal from the hand-drive pulsegeneration circuit 405-a applied to it, the AND gate 452 has applied toit the output signal form the low-voltage hand-drive pulse generationcircuit 405-d applied to it, the AND gate 453 has the output signal fromthe fast-forward pulse generation circuit 405-e applied to it, the ANDgate 454 has applied to it the output signal from the low-voltagefast-forward pulse generation circuit 405-f applied to it, and the ANDgate 455 has applied to it the output signal from the reverse-rotationpulse generation circuit 405-g applied to it. The AND gate 451, AND gate453, and the AND gate 455 are controlled directly by the output signalof the voltage level discrimination circuit 410-1, and the AND gates 452and 454 are controlled by the output signal of the voltage leveldiscrimination circuit 410-1 via an inverter 423, the output signals ofthe AND gates 451, 452, 453, 454, and 455 being applied to the inputs ofan OR gate 456, the output of which is applied to the T input of thetoggle flip-flop 417 and to the AND gates 418 and 419.

The reference numeral 417 denotes a toggle flip-flop, the Q and Q-baroutputs of which invert at the rising edge of the output of the OR gate456, the Q output signal controlling the AND gate 418, an the Q-baroutput controlling the AND gate 419 The reference numeral 407 denotes adrive circuit, which comprises a known configuration of two p-channelMOS transistors and two n-channel MOS transistors.

The reference numeral 421 denotes a coil of the stepping motor 406,which is connected to the output terminal of the drive circuit 407, and422 is the rotor of the stepping motor, the rotation of this rotor 422being transmitted via a watch gear train (not shown in the drawing) thesecond hand 30, minute hand 31, and hour hand 32 which are shown in FIG.12.

The reference numerals S1, S2 and S3 each denote a switch, each beingconnected to the power supply VSS during normal hand drive.

That is, in this example, a means for detecting the power supply voltageis used as the non-proper condition detection means 410, and a selectiveswitching circuit 450 which selects the drive pulses is used as thecontrol mode-changing instruction means 411.

With regard to the above-noted configuration, first the normalhand-drive operation when the power supply voltage is 1.2 V or greaterwill be described. During normal hand drive, signals are output from thehand-drive pulse generating circuit 405-a and the low-voltage hand-drivepulse generation circuit 405-d. However, because the power supplyvoltage is 1.2 V or greater the AND gate 451 is in the on condition, andthe AND gate 452 is in the off condition. Therefore, the hand-drivepulse which is the output signal from the hand-drive pulse generationcircuit 405-a passes through the OR gate 456 and is applied to thetoggle flip-flop 417, and to the AND gate 418 and the AND gate 419. Ifon the first hand-drive pulse the Q output of the toggle flip-flop 417is high, the AND gate 418 is turned on, so that the hand-drive pulse isapplied via the AND gate 418 to the drive circuit 407. For this reason,current flow in the coil 421, and the rotor 422 rotates one step in theforward direction. On the next hand-drive pulse, because the toggleflip-flop 417 Q-bar output is high, the AND gate 419 is turned on, sothat the hand-drive pulse is applied via the AND gate 419 to the drivecircuit 407.

For this reason, current flows in the coil 421 in the reverse direction,and the rotor 422 rotates another step in the forward direction. In thismanner, the stepping motor rotates one step at a time in the forwarddirection, so that the second hand 30, minute 31, and hour hand 32 shownin FIG. 12 are driven to display the time.

Next, the operation of correcting hand position with a power supplyvoltage of 1.2 V or greater will be described. Before that, however, theoperation of rotating the stepping motor forward to correct the handposition will be described.

First, by pulling the stem 33 shown in FIG. 12, which is the externaloperating element, out to the first step, the switch S1 which is shownin FIG. 10 is connected to the power supply VDD, the last stage of thefrequency divider circuit 404 being reset, and the generation of theoutput signals form the hand-drive pulse generation circuit 405-a andthe low-voltage hand-drive pulse generation circuit 405-d being stopped.Next, when the pushbutton 34 which is the external operating elementshown in FIG. 12 is pushed in, the switch S2 is connected to VDD, and ahigh signal is applied, via the fast-forward pulse generation circuit405-e and the OR gate 424, to the low-voltage fast-forward pulsegeneration circuit 405-f. If this switch is pressed continuously forlonger than 1 second, the output signals from the fast-forward pulsegeneration circuit 405-e and the low-voltage fast-forward pulsegeneration circuit 305-f are generated continuously and applied to theAND gate 453 and the AND gate 454, respectively. However, because thepower supply voltage is 1.2 V or greater, the AND gate 453 is in the oncondition, and the AND gate 454 is in the off condition, so that theoutput of the fast-forward pulse generation circuit 405-e is applied tothe drive circuit 407 via the OR gate 456 and the AND gate 418. For thisreason, the rotor is fast-forwarded in the forward direction so as tocorrect the hand position. When the depressed condition of thepushbutton 34 is released, the force of a spring (not shown in thedrawing) once again connects the switch S2 to the power supply VSS, sothat operation of correction of the hand position is no longerperformed.

If the pushbutton 34 is released before it is held depressed for 1second, only one pulse is generated. Thereafter, if the stem 33 ispushed in the switch S1 is again connected to VSS, the reset conditionof the frequency divider circuit 404 being released, so that return ismade to the normal hand drive condition. If the stem 33 is pulled out tothe second step, it is possible via the rear gear train, in the samemanner as with a general watch, to correct the position of the minutehand 31 and the hour hand 32 only. When the stem 33 is pulled out to thesecond step, by the action of levers (not shown in the drawing) it is nolonger possible to push in the pushbuttons 34 and 35.

Next, the cast in which hand position correction is performed by reverserotation of the stepping motor will be described.

After pulling out the stem 33 shown in FIG. 12, which the first externaloperating element, when the pushbutton 35 shown in FIG. 12 which is thethird external operating element is pressed, the switch S3 is connectedto VDD, so that a high signal is applied to the low-voltage fast-forwardpulse generating circuit 405-f, via the reverse-rotation pulsegeneration circuit 405-g and the OR gate 424. If this is pressedcontinuously for longer than 1 second, the output signals from thereverse-rotation pulse generation circuit 405-g and the low-voltagefast-forward pulse generation circuit 405-f will be output continuouslyand applied to the AND gate 454 and the AND gate 455, respectively.However, because the power supply voltage is 1.2 V or greater, the ANDgate 454 is in the on condition and the AND gate 455 is in the oncondition, so that only the output signal form the reverse-rotationpulse generation circuit 405-g is applied to the drive circuit 407, viathe OR gate 456 and the AND gate 418.

For this reason, the rotor 422 is fast-reversed so as to correct thehand position. If the depressed condition of the pushbutton 35 isreleased, the force of a spring (not shown in the drawing) acts toconnect the switch S3 to VSS once again, so that the operation of handposition correction is no longer performed.

If the pushbutton 35 depressed condition is released after a period oftime shorter than 1 minute, only one group of reverse-rotation pulses isgenerated. Thereafter, if the stem is pushed in, the switch S1 is againconnected to VSS, the reset condition of the frequency divider circuit404 is released, and normal hand drive is performed.

Next, the operation of normal hand drive at a power supply voltage ofless than 1.2 V will be described.

When the power supply voltage falls below 1.2 V, a low signal from thevoltage level discrimination circuit 410-1, that is, a low-voltagediscrimination signal is generated, and because the AND gate 451 of thecontrol circuit 450 is turned off and the AND gate 452 of the controlcircuit 450 is turned on, in this condition a hand-drive pulse, which isthe output signal from the low-voltage hand-drive pulse generationcircuit 405-d, is applied to the drive circuit 407 via the OR gate 456.

As a result, reverse current flow alternately in the coil 421, thiscausing the rotor 422 to rotate in the forward direction, althoughnon-regularly every 2 seconds, rather than the normal rotation. By meansof this rotation, the second hand 30, the minute hand 31, and the hourhand 32 as shown in FIG. 12, are driven. The non-regular hand driveevery 2 seconds indicates to the user that the power supply voltage hasdropped.

Next, the operation of correction of the hand position when the powersupply voltage is less lower than 1.2 V will be described, first for thecase in which the pushbutton 34 is pressed to correct the hand position.

When the stem 33 shown in FIG. 12 is pulled out to the first step, asdescribed earlier, the generation of output signals by the hand-drivepulse generation circuit 405-a and the low-voltage hand-drive pulsegeneration circuit 405-d is stopped. Next, if the pushbutton 34 shown inFIG. 12 is pressed continuously, as described earlier the output signalsfrom the fast-forward pulse generation circuit 405-c and the low-voltagefast-forward pulse generation circuit 405-f are generated continuously,these being applied to the AND gate 453 and the AND gate 454,respectively.

However, because the power supply voltage is less than 1.2 V, the ANDgate 453 is now in the off condition and the AND gate 454 is in the oncondition, so that the low-voltage fast-forward pulse generation circuit405-f is applied, via the OR gate 456, to the drive circuit 407. As aresult, the rotor 422 is rotates at high speed (fast forward) in theforward direction so as to correct the hand position. Under thiscondition, the pulse width is wider than the pulse width is at 1.2 V orhigher power supply voltage, and the drive frequency is low, so thatnormal operation of the stepping motor is possible down to approximately0.8 V. If the depressed condition of the pushbutton 34 is released, theswitch S2 is once again connected to VSS, and the hand positioncorrection operation is stopped.

Thereafter, if the stem 33 is pushed in, the switch S1 is once againconnected to VSS, thereby releasing the reset condition of the frequencydivider circuit 404, resulting in the non-regular hand movement every 2seconds.

Next, the case of pressing the pushbutton 35 to correct the handposition when the power supply voltage is less than 1.2 V will bedescribed.

If after pulling out the stem 33 which is shown in FIG. 12 thepushbutton 35 is pressed continuously, as described earlier the outputsignals of the low-voltage fast-forward pulse generation circuit 405-fand the reverse-rotation pulse generation circuit 405-g are generatedcontinuously and applied to the AND gate 454 and the AND gate 455,respectively. However, because the power supply voltage is less than 1.2V, the AND gate 454 is on and the AND gate 455 is off, so that only theoutput signal from the low-voltage fast-forward pulse generation circuit405-f is applied, via the OR gate 456, to the drive circuit 407. Forthis reason, the rotor 422 rotates at high speed in the forwarddirection to correct the hand position.

That is, even if the pushbutton 35 is pressed, at a power supply voltageof less than 1.2 V, reverse-rotation operation is not performed. If thedepressed condition of the pushbutton 35 is released, the switch S3 isonce again connected to VSS, and the correction of hand position isstopped. Thereafter, if the stem 33 is pushed in, the switch S1 is againconnected to VSS, resulting in release of the reset condition of thefrequency divider circuit 404, so that non-regular hand movement every 2seconds occurs.

In the above-described embodiment, while the description of fast-forwardoperation and reverse-rotation operation was for the case of correctingthe hand position for the display of the time, the present inventiondoes not necessarily impose such a limitation, and variations arepossible wit the scope of the essence of the present invention. Forexample, the essence of the present invention includes application toposition correction of alarm time display hands, and initial positionreset of the stopwatch hand of an electronic watch which has a stopwatchfunction.

In the above-noted aspect of the present invention, when the powersupply voltage falls below a prescribed voltage, reverse-rotationoperation of a stepping motor, which is difficult at a low voltage, isprohibited, the width of the forward drive pulse is increased and,because the drive speed is made low, the stepping motor is operated withgood stability even at a low voltage, the resulting effect being large.

Next, a specific example of the second aspect of the electronic watch400 according to the present invention will be described, with referencebeing made to FIG. 13 and FIG. 14.

Specifically, FIG. 13 is a general block diagram of an example of thesecond aspect of the electronic watch 400 according to the presentinvention, this comprising the power supply 401 and the watch circuit402.

In this electronic watch, the watch circuit 402 comprises an oscillatorcircuit 403, a frequency divider circuit 404, a drive pulse generationmeans 405, a drive motor 406 which, in response to the drive pulse P1which is output by the above-noted drive pulse generation means 405,drives at least one of an hour/minute, second, and chronograph hand, adrive circuit means 407 which controls the drive of the above-noteddrive motor 406, a drive circuit control means 408 which controls theabove-noted drive circuit means 407, and a control condition detectionmeans 409 which is connected to the above-noted drive circuit controlmeans 408 and which detects a control condition in the above-noted drovecircuit control means 408. In this electronic watch, the above-noteddrive pulse generation means 405 minimally comprises a normal hand-drivepulse generation circuit 405-a, a compensation drive pulse generationcircuit 405-b, and a chronograph display fast-forward (high-speed) pulsegeneration circuit 405-h, the above-noted drive motor 406 and drivecircuit means 407 therefor comprising a first drive motor 406-1 which isdriven by the above-noted normal hand-drive pulse, a first drive circuitmeans 407-1, a second drive motor 406-2 which is driven by a high-speedpulse which is higher in speed than the above-noted normal hand-drivepulse, and a second drive circuit means 407-2.

Furthermore, in this electronic watch the above-noted control conditiondetection means 409 detects whether or not the above-noted first drivemotor 406-1 rotated in response to a prescribed drive pulse supplied bythe above-noted first drive circuit means 407-1 and includes a loadcompensation control system 500 which, if a judgment is made that thefirst drive motor 406-1 did not rotate, supplies a prescribedcompensation drive pulse Ph to the circuit means 407-1 to therebycompensate the first drive motor 406-1, and further the drive circuitcontrol means 408 of this electronic watch 400 being provided with anon-proper condition detection means 410 which comprises a monitorcircuit 410-2 that monitors the rotation condition of the above-notedsecond drive motor 406-2, whereby, in response to the output from theabove-noted non-proper condition detection means 410 of a detectionsignal which indicates a non-proper rotation condition of theabove-noted second drive motor 406-2 is output, and means 411-2 forstopping the execution of the load compensation control system 500 withrespect to the above-noted first drive motor 406-1, this being provideas a control mode changing instruction means 411.

In another example of this aspect of the electronic watch 400, in theabove-noted configuration, when the control mode change-instructingmeans 411 stops the execution of the load compensation control system500 by means of the detection signal from the above-noted non-propercondition detection means 410, the above-noted compensation drive pulsePh is supplied to the first drive motor 406-1.

That is, in this example in particular, the monitor circuit 410-2 whichmonitors the drive condition of a drive motor to prevent the intrusionof magnetic noise interference from a neighboring drive motor therein isused as a non-proper condition detection means 410 of the controlcondition detection means 409, and a means for stopping the execution ofthe load compensation control system 500 is used as the above-notedcontrol mode change-instructing means 411.

The above-noted example is describe in detail below.

Specifically, the electronic watch 400 in this example has a motor drivecircuit 405 which generates a normal drive pulse and a compensationdrive pulse, a first motor 406-1 which is controlled by detection ofnon-rotation by the detection circuit 501 and which is compensated bythe load compensation circuit 502, and a second drive motor 406-2 whichis driven at high speed by a high-speed pulse having a frequency of 1 Hzor higher, and further has a control mode change-instructing means 411 aload compensation disabling means 411-2 whereby, when the above-notedsecond drive motor 406-2 is driven at high speed, the load compensationoperation with respect to the first drive motor 406-1 is prohibited.Furthermore, the above-noted motor drive circuit 407-1 supplies acompensation drive pulse Ph to the above-noted first drive motor 406-1by means of the above-noted load compression disabling means 411-2.

Next an embodiment of the present invention will be described in detail,with reference made to accompanying drawings. FIG. 13 is a block diagramof this specific example of the electronic watch 400, and FIG. 14 is awaveform drawing of the waveforms that are output by the electronicwatch which is shown in FIG. 13. The module configuration of thisembodiment is basically the same as in examples in the past.

In FIG. 13, the reference numeral 406-1 is a first stepping motor forthe purpose of displaying the time, 406-2 is a second stepping motor forthe purpose of displaying a chronograph, 407-1 is a first motor drivecircuit for the purpose of driving the above-noted first stepping motor406-1, and 407-2 is a second motor drive circuit for the purpose ofdriving the above-noted second stepping motor 406-2. In the samedrawing, the reference numeral 403 is an oscillator circuit, 404 is afrequency divider circuit, 405-a is a normal drive pulse generationcircuit which generates a normal drive pulse P1, 405-b is a compensationdrive pulse generation circuit which generates a compensation drivepulse Ph, 405-c is a rotation detection signal generating circuit whichgenerates the coil switching pulses Pk1 through Pk8 which cause theinduction of voltages for the detection of rotation, 501 is a detectioncircuit which detects an induced voltage of the first stepping motor406-1, 502 is a load compensation control circuit which makes a judgmentof rotation and non-rotation by means of a signal of the detectioncircuit 501, a load compensation control system 500 being formed by thedetection circuit 501 and the load compensation control circuit 502, and408 is a first motor control circuit which outputs a compensation drivepulse Ph for the non-rotation condition according to the signal for theload compensation control circuit 502. Additionally, 405-1 is achronograph pulse generating circuit which generates a chronographpulse, 511 is a chronograph control circuit which supplies to the secondmotor drive circuit 407-2 a chronograph pulse P11 which is generated bythe chronograph pulse generation circuit 405-h and which is controlledby the S switch 516 and or the R switch 517, 409 is a control conditiondetection means which comprises the non-proper condition detection means410-2 that recognizes the operation condition of the second drive motor406-2 from the existence or non-existence of a signal from thechronograph control circuit 517, and the control mode change-instructioncircuit 411-2 which supplies the compensation drive pulse Ph that isgenerated by the compensation drive pulse generating circuit 105 to thefirst drive motor 406-1.

Next the operating of the above-noted circuit will be described. Theoscillator circuit 403 outputs a signal having a frequency of 32768 Hz,based on a quartz crystal, and the frequency divider circuit 404frequency divides this signal. The normal drive pulse generation circuit405-a generates a normal drive pulse P1 as shown in FIG. 14 (a) every 1second, based on a signal of the frequency divider circuit 404.

The normal drive pulse P1, as describe with regard to an example of thepast, is a pulse having a width of 5 ms and a pulse resting period of1.4 ms each 1 ms. The compensation drive pulse generation circuit 405-bgenerates a compensation drive pulse Ph as shown in FIG. 14 (b), basedon a signal from the frequency divider circuit 404. The compensationdrive pulse Ph is a 10-ms pulse that is delayed 32 ms with respect tothe normal drive pulse P1. Additionally, the compensation drive pulsegeneration circuit 405-b generates a compensation drive pulse Ph asshown in FIG. 14 (c), based on a signal from the frequency dividercircuit 404, this pulse being output every 1 second.

During normal operation, that is, when the chronograph is not operating,the chronograph 7 is stopped at the 0 position, as shown in FIG. 4. Inthis condition, the chronograph control circuit 511 outputs a low-levelsignal as an S control signal. The non-proper condition detection means410-2, which is a selector gate, receives the low-level control signalS, in response selects a pulse which is output from the first motorcontrol circuit 408, and supplies this to the first motor drive circuit407-1.

The first motor drive circuit 407-1 has supplied to it with a 1-secondtiming, via the control condition detection means 409 which includes thenon-proper condition detection means 410-2, the normal drive pulse P1,resulting in normal drive of the first stepping motor 406-1.Additionally, the coil switching pulses Pk1 through Pk8, which areoutput by the rotation detection signal generation circuit 406-c aresupplied to the first motor drive circuit 407-1, via the first motorcontrol circuit 408 and the control condition detection means 409, andwhether or not the induced voltage at that time exceeds a thresholdvoltage Vth is detected by the detection circuit 501. The results ofthis detection are transmitted to the load compensation control circuit502, thereby making a judgment of rotation and non-rotation, the methodof making this judgment being exactly the same as described with regardto the example of the past illustrated by FIG. 2 and FIG. 3. Then, ifthe load compensation control circuit 502 makes the judgment thatrotation occurred, it controls the first motor control circuit 408 sothat a compensation drive pulse Ph is not output. If, however, thejudgment is made that rotation did not occur, it performs control of thefirst motor control circuit 408 so that a compensation drive pulse Ph isoutput.

Thus, if it is not possible with the normal drive pulse P1 to drive thefirst stepping motor 406-1, the compensation drive pulse Ph drives themotor once again so that the watch does not lag.

Next, when the S switch 516 is turned on, the chronograph is started,placing the chronograph in the operating condition. At this time, thechronograph control circuit 511 outputs a high-level control signal S.

In response to this high-level control signal S, the chronograph pulsegeneration circuit 405-h outputs to the second motor drive circuit 407-2a chronograph pulse P11 as shown in FIG. 14 (d) each 10 ms. Then thesecond stepping motor 406-2 rotates forward at a high speed of 10 Hz,chronograph hand 7 being move at a high speed as the chronographoperates. The control condition detection means 409 receives thehigh-level control signal S from the chronograph control circuit 511,and in response switches from the condition of selection of theabove-noted first motor control circuit 408 to the condition ofselection of the compensation pulse generation circuit 405-b, therebysupplying a compensation pulse Ph to the first motor drive circuit407-1. By doing this, the compensation pulse Ph is supplied to the firststepping motor 406-1 every 1 second. Furthermore, to assure reliablerotation the compensation pulse Ph has a width of 10 ms, which is largerthan the normal drive pulse P1.

During the period in which the chronograph is in the operationcondition, that is, during the period in which the second stepping motor406-2 is rotating at high speed, load compensation operation withrespect to the first stepping motor 406-1 is prohibited, and drive isdone with the compensation pulse Ph. That is, in this embodiment theabove-noted control condition detection means 409 includes a loadcompensation disabling means 411-2, that is, the control modechange-instructing means 411-2 which, while the second stepping motor406-2 is rotating at high speed, prohibits load compensation operationwith respect to the first stepping motor 406-1.

In addition, when the S switch is turned on, the stop operation isperformed, the control signal S of the chronograph control circuit 511being reset to the low level. The chronograph pulse generation circuit405-h output of the chronograph pulse P1 is stopped by means of thislow-level control signal S, this causing the stoppage of the rotation ofthe second stepping motor 406-2. Simultaneous with this, the controlcondition detection means 409 receives the control signal S, resultingin selection once again of the pulse which is output by the first motorcontrol circuit 408, this causing restarting of the load compensationoperation.

Next, when the R switch 517 is set to on, the reset operation isperformed, this causing the chronograph hand 7 to be reset to the 0position at high speed at this time as well, the operation performed issimilar to the above-described case of chronograph operation, That is,by means of the reset operation, the chronograph control circuit 511goes into the condition in which it outputs a high level control signalS. The chronograph pulse generation circuit 405-h, in response to thighhigh-level control signal S, outputs a chronograph pulse P11 to thesecond motor drive circuit 407-2. The second stepping motor 406-2, inresponse to this chronograph pulse P11, performs high-speed rotation at100 Hz, thereby moving the chronograph hand 7 to the 0 position. Thecontrol condition detection means 409, in response to receiving thehigh-level control signal S from the chronograph control circuit 511,switches from the condition of selection of the above-noted firststepping motor control circuit 408 to the condition of selection of thecompensation pulse generation circuit 405-b, this causing supply of thecompensation pulse Ph to the first motor drive circuit 407-1. The resultis that the first stepping motor 406-1 and the chronograph hand 7 aredriven by the compensation pulse Ph every 1 second until return is madeto 0.

When the return of the chronograph hand 7 to 0 is completed, thechronograph control circuit 511 returns to the condition in which itoutputs a low-level control signal S. Then, in response to thislow-level control signal S, the chronograph pulse generation circuit405-h stops output of the chronograph pulse P11. Simultaneous with this,the control condition detection means 409, in response to this low-levelcontrol signal S, once again returns to the condition of selection ofthe first motor drive circuit 408, this causing restarting of the loadcompensation.

In the above-noted embodiment, while the description is for the case inwhich one type of the normal drive pulse P1 is made available, in thepast there has been a know a method in which a plurality of types ofnormal drive pulse provided, the drive pulse being selected therefrom asthe smallest drive pulse capable of providing drive. The presentinvention provides the same type of effect with regard to this method aswell. As is clear from the above description, according to the presentinvention the current consumption of the first stepping motor 406-1 isnormally limited by load compensation operation, and when chronographoperation or the like is performed, the load compensation operation, inwhich there is a risk of erroneous detection, is stopped therebypreventing misoperation. Additionally, in this case by driving with acompensation pulse which is larger than the normal drive pulse, reliabledrive is ensured. The effect of using the above-noted system is that itis possible to have a design in which the first stepping motor 406-1 andsecond stepping motor 406-2 are located in proximity on the same plane.

The present invention solves the above-noted problem and enables theprovision of an electronic watch which, by preventing misoperation ofthe load compensation operation caused by externally introduced magneticinterference from a neighboring stepping motor, keeps tie withoutdisturbance therefrom.

Next, a specific example of the third aspect of the electronic watch 400according to the present invention will be described, with referencebeing made to FIG. 15 through and FIG. 18.

Specifically, FIG. 15 is a general block diagram of an example of thethird aspect of the electronic watch 400 according to the presentinvention, this comprising the power supply 401 and the watch circuit402. In this electronic watch, the watch circuit 402 comprises anoscillator circuit 403, a frequency divider circuit 404, a drive pulsegeneration means 405, a drive motor 406 which, in response to the drivepulse P1 which is output by the above-noted drive pulse generation means405, drives at least one of an hour/minute, second, and chronographhand, a drive circuit means 407 which controls the drive of theabove-noted drive motor 406, a drive circuit control means 408 whichcontrols the above-noted drive circuit means 407, and a controlcondition detection means 409 which is connected to the above-noteddrive circuit control means 408 and which detects a control condition inthe above-noted drive circuit control means 408.

In this electronic watch, the above-noted drive pulse generation means405 minimally comprises a normal hand-drive pulse generation circuit601, and a non-normal hand-drive pulse generation circuit 605 whichgenerates a non-normal drive pulse that differs from the normalhand-drive pulse, the configuration further comprising a first drivemotor 406-1 and a first drive circuit means 407-1 which are driven bythe above-noted normal hand-drive pulse, a second drive motor 406-2 anda second drive circuit means 407-2 which are driven by the above-notednon-normal hand-drive pulse, the configuration additionally being suchthat, from the above-noted normal hand-drive pulse generation circuit601 and above-noted non-normal hand-drive pulse generation circuit 605,a plurality of normal hand-drive pulses Ps and a compensation pulsesPsh, these having mutually differing drive capacities, and a pluralityof non-normal hand-drive pulses Pc and compensation pulses Pc1, thesealso having mutually differing drive capacities, the above-noted drivecircuit control means 408-1 including a load compensation control system500 which detects the rotation and non-rotation of the first drive motor406-1 in response to a prescribed drive pulse which is supplied to thefirst drive circuit means 407-1 and, in the case in which it is judgedthat the first drive motor 406-1 did not rotate, supplies a prescribedcompensation drive pulse Psh to the above-noted first drive circuitmeans 407-1 so as to compensation the rotation of the first drive motor406-1.

In addition the above-noted control condition detection means 409 ofthis electronic watch is provided with a non-proper condition detectionmeans 410 which comprises an output means 410-3 that outputs predictedvoltage information of the power supply from the output voltage in theload compensation control system, and a control mode change-instructingmeans 411 which comprises a selection circuit 611 and/or 615 thatselects, based on the information of the above-noted non-propercondition detection means 410, at least one drive pulse from at leastone pulse group of the plurality of normal hand-drive pulse groups andnon-normal hand-drive pulse groups which are output, respectively, fromthe above-noted normal hand-drive pulse generation circuit 601 and theabove-noted non-normal hand-drive pulse generation circuit 605.

The above-noted non-normal hand-drive pulse generation circuit 605 inthis example includes at least one of a high-speed pulse generationcircuit and a reverse-rotation pulse generation circuit.

That is, in this example, a predicted voltage information output means410-3 which outputs predicted voltage information of the power supplyvoltage from the output voltage in the load compensation control systemis used a the non-proper condition detection means 410 of the controlcondition detection means 409, and a selection circuit 611 and or thatselects, based on the information of the above-noted non-propercondition detection means 410, at least one drive pulse form at leastone pulse gruop of the plurality of normal hand-drive pulse groups andnon-normal hand-drive pulse groups which are output, respectively, fromthe above-noted normal hand-drive pulse generation circuit 601 and theabove-noted non-normal hand-drive pulse generation circuit 605 is usedas the control mode change-instruction means 411.

The above-noted example is described in detail below.

Specifically, the electronic watch 400 in the above-noted examplecomprises an electrical power supplying means 401, a first steppingmotor 406-1, a normal pulse generating means 601 which generates aplurality of normal pulses having mutually differing drive capacitiesfor the purpose of driving the above-noted first stepping motor 406-1, anormal pulse selection means 611 which selectively outputs one normalpulse from the above-noted plurality of pulses, a detection means 630which detects rotation and non-rotation of the above-noted firststepping motor 406-1, and a load compensation control circuit 620 whichestablishes the selection condition for the above-noted normal pulseselection means 611, in accordance with a detection signal of theabove-noted detection means 630, a second stepping motor 406-2, anon-normal pulse generation means 605 which generates a plurality ofnon-normal pulses having mutually differing drive capacities for thepurpose of driving the above-noted second stepping motor 406-2, and anon-normal pulse selection circuit 615 which selectively outputs one ofthe above-noted plurality of non-normal pulses being further provided,the selection condition of the pulse selection circuit 615 beingestablished by means of the power supply voltage prediction means 401-3which is connected to the above-noted load compensation control circuit620.

That is, in this example, the power supply voltage prediction means410-3 corresponds to the non-proper condition detection means 410, andthe pulse selection circuits 611 and 615 correspond to the control modechange-instructing means 411.

Furthermore, in this example the electrical power supplying means 401 isa rechargeable electrical power supplying means, which includes a solarbattery.

Next, the above-noted aspect of the embodiment of the present inventionwill be described in detail, with reference made to the appropriateaccompanying drawings. FIG. 16 is a plan view of an electronic watch ofthis aspect of an embodiment of the present invention, in which thereference numeral 400 denotes the electronic watch, 406-1 is the firststepping motor, 814 is a second gear train, and 815 is a second hand.The first stepping motor 406-1 drives the second hand 815 via the secondgear train 814. In this same drawing, 406-3 is a second stepping motor,824 is an hour/minute gear train, 825 is a minute hand, and 826 is anhour hand. The second stepping motor 406-3 drives the minute hand 825and the hour hand 826 via the hour/minute gear train 824. The referencenumeral 406-2 denotes a third stepping motor, 834 is a chronograph geartrain, and 835 is a chronograph hand.

The third stepping motor 406-3 drives the chronograph hand 835 via thechronograph gear train 834. The reference numeral 840 denotes a watchface which comprises a solar cell, onto which hour markings 841, achronograph scale 843, a time mode mark 861, an alarm mode mark 862, anda chronograph mode mark 863 are printed. The reference numeral 853denotes a an M button which switches between the time mode, the alarmmode, and the chronograph mode, 851 is an S button which starts andstops the chronograph, 852 is an R button which resets the chronograph,and 850 is a correction button for correcting the time. The referencenumeral 860 is a mode hand which is mechanically driven by the M button860, this pointing to one of the time mode mark 861, the alarm mode mark862, the chronograph mark 863 to indicate the mode. The referencenumeral 880 is a calendar display part which indicates the date by beingdriven by the hour hand 826, via a gear train.

First, the functions and operation method of the electronic watch 400configured as noted above will be described, The electronic watch 400,in addition to having a normal time mode, has an alarm mode and achronograph mode function. Each time the M button 853 is pressed,sequential switching is performed of the mode hand 860 between the timemode mark 861, the alarm mode mark 862, and the chronograph mode mark863 to indicate the selected mode, the electronic watch 400 functioningin the mode indicated thereby.

The electronic watch 400 shown in FIG. 16 is shown in the normal timemode, the mode hand 860 pointing at the time mode mark 861, in whichcondition the second hand 815, the minute hand 825, and the hour hand826 are indicating the time 10:10:35, and the date plate 881 of thecalendar display part 880 is indicating the date of the 15th. In thenormal time mode, the mode hand 860 points to the time mode mark 861,the secondhand 15 performing a normal second display by being advancedevery 1 second by the first stepping motor 406-1, the minute hand 825,hour hand 826, and date plate 881 being driven every 20 seconds by thesecond stepping motor 406-3 to indicate the minute, the hour, and thedate. Furthermore, when the time reaches 0:00, gears mesh and the dateplate 881 is advanced by one day in short period of time, at which timethe drive load is larger than usual, making it difficult for the secondstepping motor 406-3 to rotate. The pulse control when this loadvariation occurs is described below.

When the M button 853 is pressed in the normal time mode, the mode hand860 moves from the time mode mark 861 so as to point to the alarm modemark 862, and a switch is made to the alarm mode. The second steppingmotor 406-3 is rotated at high speed at 64 Hz, the minute hand 825 andhour hand 826 being driven in the clockwise direction so as to indicatethe set alarm time. If the correction button 850 is pressed continuouslywhen in this alarm mode, the second stepping motor 406-3 is rotated at ahigh speed of 64 Hz, so that the minute hand 825 and the hour hand 826are driven clockwise to correct the alarm time. If the correction buttonis released, the second stepping motor 406-3 stops, the time pointed toby the minute hand 825 and the hour hand 826 at that point being set asthe alarm time. The above operations can be used to correct the alarmtime. Furthermore, the second hand 815 continues to indicate the secondin the alarm mode as well, this being driven every 1 second by the firststepping motor 406-1.

If at the point the M button 853 is pressed once again, the mode hand860 moves from the alarm mode mark 862 so as to point to the chronographmode mark 863, and a change is made to the chronograph mode. The secondstepping motor 406-3 is driven in reverse at 32 Hz, the minute hand 825and the hour hand 826 being drive counterclockwise so as to change fromthe alarm time to the normal time display. The chronograph hand 835, asshown in FIG. 16, is stopped at the 12-o'clock position. If the S button851 is pressed when in the chronograph mode, the chronograph hand 835starts to move in chronograph operation.

Then if the S button 851 is pressed once again, the stop operation isperformed, the third stepping motor 406-2 stopping and the chronographhand 835 indicating the stopping position. Then if the R button 852 ispressed, a reset is performed, the third stepping motor 406-2 beingdriven at a high forward speed of 100 Hz, and the chronograph hand 835moving to and stopping at the 12-o'clock position. Furthermore, in thechronograph mode, the second hand 815 continues to indicate the secondof the normal time, this hand being advanced every 1 second by the firststepping motor 406-1.

Next, the circuit operation related to the above will be described. FIG.15 is a block diagram which shows the system of the electronic watch 400shown in FIG. 16. In FIG. 15, the reference numeral 401 denotes a solarcell which generates electrical energy by means of light, 570 is anelectrical double-layer capacitor that stores electrical energy, and 402is a watch circuit which is operated by the electrical energy that isstored in the electrical double-layer capacitor 570.

In the same FIG. 15, 403 is an oscillator circuit which generates thereference clock necessary for circuit operation, 404 is a frequencydivider circuit which frequency divides the reference clock generated bythe oscillator circuit 403, 601 is a first normal pulse generationcircuit that generates normal pulses Ps1 to Ps8 for the purpose ofnormal drive of the first stepping motor 406-1 and a compensation pulsePh for the purpose of compensation drive, 602 is a second normal pulsegeneration circuit that generates normal pulses Pm1 to Pm8 for thepurpose of normal drive of the second stepping motor 406-3 and acompensation pulse Pmb for the purpose of compensation drive, 603 is asecond high-speed pulse generation circuit that generates high-speedpulses Pf1 to Pf4 for the purpose of driving the second stepping motor406-3 at a high speed of 64 Hz, 604 is a second reverse-rotation pulsegeneration circuit that generates reverse-rotation pulses Pb1 to Pb4 forthe purpose of rotating the second stepping motor 406-3 in reverse at 32Hz, 605 is a third high-speed pulse generation circuit that generateshigh-speed pulses Pc1 to Pc8 for the purpose of driving the secondstepping motor 406-3 at a high speed of 100 Hz, 611 is a first normalpulse selection circuit which selects one normal pulse Ps from thenormal pulses Ps1 to Ps8 which are generated by the first normal pulsegeneration circuit 601, 612 is a second normal pulse selection circuitwhich selects one normal pulse Pm of the normal pulses Pm1 to Pm8 thatare generated by the second normal pulse generation circuit 602, 613 isa second high-speed pulse selection circuit which selects one high-speedpulse Pf from the high-speed pulses Pf1 to Pf4 that are generated by thesecond high-speed pulse generation circuit 603, 614 is a secondreverse-rotation pulse selection circuit which selects onereverse-rotation pulse Pb from the reverse-rotation pulses Pb1 to Pb4that are generated by the second reverse-rotation pulse generationcircuit 604, 615 is a third high-speed pulse selection circuit whichselects one high speed pulse Pc from the high-speed pulses Pc1 to Pc8that are generated by the third high-speed pulse generation circuit 605,650 is a timekeeping control circuit which performs control of thetimekeeping, alarm, and chronograph functions, based on a signal fromthe frequency divider circuit 404, 407-1 is a first drive circuit forthe purpose of driving the first stepping motor 406-1, 621 is asecond-hand drive circuit control means which is controlled by thetimekeeping control circuit 650 and which supplies a normal pulse Ps,which is output by the first normal pulse selection circuit 611, to thefirst drive circuit 407-1, 630 is a first detection circuit whichdetects rotation and non-rotation of the first stepping motor 406-1, 620is a first load compensation control circuit which, based on the resultsof the first detection circuit 630, controls the first normal pulseselection circuit 611 and the third high-speed pulse selection circuit,407-3 is a second drive circuit for the purpose of driving the secondstepping motor 406-3, 623 is a minute-hand drive circuit control meanswhich is controlled by the timekeeping control circuit 650 and whichselectively outputs and supplies to the second drive circuit 407-3 arequired pulse from the normal pulse Ps which is output by the secondnormal pulse selection circuit 612, the normal pulse Pf which is outputby the second high-speed pulse selection circuit 613, and thereverse-rotation pulse Pb which is output by the second reverse-rotationpulse selection circuit 614, 631 is a second detection circuit whichdetects rotation and non-rotation of the second stepping motor 406-3,622 is a second load compensation control circuit which, based on thejudgment results of the second deletion circuit 631, controls the secondhigh-speed pulse selection circuit 613 an the second reverse-rotationpulse selection circuit 614, 407-2 is a third drive circuit for thepurpose of driving the third stepping motor 406-2, 624 is a chronographhand control circuit which is controlled by the timekeeping controlcircuit 650, and which supplies a high-speed pulse Pc that is outputfrom the third high-speed pulse selection circuit 615 to the third drivecircuit 407-2 in response to the start of the chronograph, 655 is amisoperation prevention circuit which prevents misoperation caused by animproper high-speed pulse Pf or reverse-rotation pulse Pb, and 505a,551a, 552a, and 553a are a correction switch, an S switch, an R switch,and an M switch that are operated by the correction button 550, the Sbutton 551, the R button 552, and the M button 553, respectively.

Although in this example a separate second-hand drive motor 406-1 andminute-hand drive motor 406-3 are used, the present invention allows asingle motor to serve as both motor 406-1 and motor 406-3.

TABLE 3 Pulse Resting Periods of Normal pulse Pm and Minimum DriveVoltage Minimum Drive Voltage Normal Pulse Pulse Resting Period withoutload with load Pm1 0.35 ms 2.5 V 2.6 V Pm2 0.3 ms 2.2 V 2.3 V Pm3 0.25ms 1.9 V 2.0 V Pm4 0.2 ms 1.7 V 1.8 V Pm5 0.15 ms 1.5 V 1.6 V Pm6 0.1 ms1.3 V 1.4 V Pm7 0.05 ms 1.1 V 1.2 V Pm8 (None) 0.9 V 1.0 V

The configuration of the normal pulse Pm and minimum drive voltage fordriving the second stepping motor 406-3 are explained hereunder.

The normal pulses Pm1˜Pm8 have entirely the same pulse configurations asthose of the normal pulses Ps1˜Ps8.

Table 3 shows the pulse resting period of the normal pulses Pm1˜Pm8generated from the second normal pulse generating circuit 602 and theminimum drive voltage in a case where a load consisting a date plate 881is provided or in a case when no load is provided.

In the case when the load of the date plate 881 is provided, the minimumdrive voltage is increased by about 0.1V comparing with the case when noload is provided.

For example, the minimum drive voltage of the normal pulse Pm3 is 1.9Vwhen no load is provided, while it becomes 2.0V when a load is provided.

On the other hand, the compensation drive pulse Pmh which is generatedwhen the determination was made that the motor could not be driven, isalso has the same pulse configuration as those of the compensation drivepulse Psh generated from the above-noted first normal pulse generationcircuit 601.

The compensation drive pulse Pmh is generated after 32 ms when thenormal pulse Pm had been generated and it has a pulse width of 2 ms andin the last 6 ms, a series of 0.5 ms pulse resting periods in every 1ms.

TABLE 4 Pulse width of high speed pulse Pf and Voltage range capable ofdriving the motor Voltage range capable of driving the motor High speedpulse Pulse width without load with load Pf1 3.2 ms 1.8˜3.8 V 1.9˜3.9 VPf2 3.6 ms 1.4˜2.8 V 1.5˜2.9 V Pf3 4.0 ms 1.0˜2.2 V 1.1˜2.3 V Pf4 4.4 ms0.8˜1.6 V 0.9˜1.7 V

TABLE 5 Pulse width of reverse rotation pulse Pb and Voltage rangecapable of driving the motor reverse Voltage range capable rotation ofdriving the motor pulse Pb Pg1 Pg2 Pg3 without load with load Pb1 1.25ms 3.25 ms 4.0 ms 1.8˜3.8 V 1.9˜3.9 V Pb2 1.5 ms 3.0 ms 5.0 ms 1.4˜2.8 V1.5˜2.9 V Pb3 2.5 ms 3.0 ms 6.0 ms 1.0˜2.2 V 1.1˜2.3 V Pb4 2.75 ms 2.75ms 7.0 ms 0.8˜1.6 V 0.9˜1.7 V

Next, the configuration of the high speed pulse Pf and the reverserotation pulse Pb and the voltage range capable of driving the motor areexplained hereunder.

The table 4 shows a chart indicating the pulse width of the high speedpulse Pf1˜Pf4 generated from the second high speed pulse generatingcircuit 603 and the voltage range capable of driving the motor in a casewhen a load consisting a date plate 881 is provided or in a case when noload is provided.

On the other hand, the table 5 shows a chart indicating the pulse widthof the high speed pulse Pb1˜Pb4 generated from the second reverserotation pulse generating circuit 604 and the voltage range capable ofdriving the motor in a case when a load consisting a date plate 881 isprovided or in a case when no load is provided.

Note that FIG. 17 shows a waveform of the reverse rotation pulse Pb usedin this embodiment.

As shown in FIG. 17, the reverse rotation pulse Pb comprises acombination of three pulses such as a positive phase pg1, a reversephage Pg2 and a positive phase Pg3.

In the table 5, a pulse width of each one of the positive phase Pg1, thereverse phase Pg2 and the positive phase Pg3 is shown.

The high speed pulse Pf1˜Pf4 have the voltage range capable of drivingthe motor as shown in the table 4, respectively, and when one of thehigh speed pulse Pf1˜Pf4 is fallen into the outside of the respectivevoltage range, the second stepping motor 406-3 cannot be driven withhigh speed.

For example, as indicated by the table 4, the high speed pulse Pf2 hasthe pulse width of 3.6 ms, while its voltage range capable of drivingthe motor shows 1.4V˜2.8V when the load comprising, for example, a dateplate, is not provided.

Therefore, when the second stepping motor 406-3 should be rotated withhigh speed with the high speed pulse Pf2 without being provided withsuch load of the date plate, the power source voltage Vc should be1.4˜2.8V.

That is to say, when the second stepping motor 406-3 is driven, it isnecessary to select the power source voltage Vc and the high speed pulsePf which is corresponding to the load consisting the date plate 881.

As the same way, the reverse rotation pulses Pb1˜Pb4 have the voltagerange capable of driving the motor as shown in the table 5,respectively, and then one of the reverse rotation pulses Pb1˜Pb4 isfallen into the outside of the respective voltage range, the secondstepping motor 406-3 cannot be driven in the reverse direction with suchpulse.

Note that when the second stepping motor 406-3 is reversely driven, itis necessary to select the power source voltage Vc and the reverserotation pulse Pb which is corresponding to the load consisting the dateplate 881.

Further note that in comparing with the fact that the high speed pulsePc which drives to rotate the third stepping motor 406-2 with high speedis driven with 100 Hz, the high speed pulse Pf which drives to rotatethe second stepping motor 406-3 with high speed is driven with 64 Hz.

For the sake of it, even though both high speed pulses Pc and Pf havethe same pulse width to each other, the voltage range capable of drivingthe motor obtained by the high speed pulse Pf is wider than thatobtained by the high speed pulse Pc.

Therefore, although in a case in which the high speed pulse Pc is used,eight different kinds of high speed pulses Pc1˜Pc8 are driven tocommonly share the voltage range of 1˜3 V with which the electronicwatch 400 can be driven, in the case in which the high speed pulse Pf isused, four different kinds of four speed pulses Pf1˜Pf4 are driven tocommonly share the voltage range of 1˜3 V with which the electronicwatch 400 can be driven.

And further, as shown in Table 4, the voltage range capable of drivingthe motor obtained by the high speed pulse Pf1, in the case of no loadbeing provided, is set at from 1.8V to 3.8V so that the motor can bedriven from a condition in which the minimum drive voltage of the normalpulse Pm2 is set at 2.2V to a condition in which the upper most of thepower source voltage Vc such as 3.0V.

As the same manner, the voltage range capable of driving the motorobtained by the high speed pulse Pf2 is set at from 1.4V to 2.8V so thatthe motor can be driven from a condition in which the minimum drivevoltage of the normal pulse Pm4 is set at 1.7V to a condition in whichthe upper most of the voltage selectively generated for the normal pulsePm3, such as 2.3V which is a minimum operation voltage of the normalpulse Pm2.

While, the voltage range capable of driving the motor of the high speedpulse Pf3 is set at between 1.0˜2.2V so that the stepping motor can bedriven from 1.3V which is the minimum drive voltage of the normal pulsePf6 to the upper limit voltage of the normal pulse Pm5 to be selectivelyoutput which corresponds to 1.7V that is a minimum operation level ofvoltage for the normal pulse Pm4.

On the other hand, the voltage range capable of driving the motor of thehigh speed pulse Pf1 is set at between 0.8-1.7V so that the electricwatch 400 can be driven from 1.0V which is the minimum drive voltagethereof to the upper limit voltage of the normal pulse Pm7 to beselectively output which corresponds to 1.3V that is a mimimum operationlevel of voltage for the normal pulse Pm6.

In the same way, these conditions can be applied to the reverse rotationpulse Pb and thus the voltage range capable of driving the motor of thereverse rotation pulse Pb1˜Pb4 are set at the same range set for thehigh speed pulses Pf1˜Pf4.

Next, an operation of the circuit with respect to a selection way of thehigh speed pulse Pf will be explained hereunder.

The second stepping motor 406-3 is driven in every 20 second in a normaltime display mode to drive the minute hand 825, hour hand 826,respectively so as to display hour and minute in normal time and furtherdrive a date plate 881.

That is to say, second stepping motor 406-3 is driven by a normal pulsePm so that multi-load compensation control circuit is carried out.

However, at every time, the driving condition usually includes not onlyvariation in power source voltage Vc but also variation in load causedby driving the date plate 881.

Namely, the second load compensation control circuit 622 controls thesecond normal pulse selection circuit 612 so that a minimum voltagelevel of the normal pulse Pm which can drive the second stepping motor406-3 with respect to voltage and load, is selected and accordingly, thecurrent total driving condition caused by the power source voltage Vcand the load of the date plate 881, can be acknowledged by the pulsewidth of the normal pulse Pm which is output at that time-being.

And thus, it would be prefer to select the high speed pulse Pf havingthe voltage range capable of driving the motor under which the motor canbe driven by even the normal pulse Pm having the minimum drive voltagelevel.

On the other hand, due to the load caused by the date plate 881, theminimum drive voltage of the normal pulse Pm is increased by about 0.1V,as well as the same voltage of the high speed pulse Pf is increased byabout 0.1V.

Therefore, there must be no problem even when the selection of the highspeed pulse Pf is carried out in the same manner as used in a case inwhich no load caused by the date plate 881 is provided, regardless theexistence of the load caused by the date plate 881.

For example, with reference to the Table 3, the range of minimum drivevoltage of the normal pulse Pm8 is 0.9V in a case of the load beingprovided and the range of minimum drive voltage of the normal pulse Pm6is 1.3V in a case of no load being provided.

Therefore, it can be acknowledged that when the normal pulses Pm8 or Pm7is output, the power voltage shows 0.9V˜1.3V.

Further, from the Table 4, it can also be acknowledged that when thenormal pulses Pm8 or Pm7 is output, the range of drive voltage of thehigh speed pulse Pf4 in a case of no load being provided, is 0.8V˜1.6V.

Accordingly, when the second stepping motor 406-3 is driven by thenormal pulse Pm8 or the normal pulse Pm7, the second stepping motor406-3 can sufficiently be driven in high speed with the high speed pulsePf4 even taking variation in mechanical elements into account.

In a case in which the load is provided, seeing from the Table 3, theminimum drive voltage range of the normal pulse Pm8 is 1.0V and theminimum drive voltage range of the normal pulse Pm6 is 1.4V.

Accordingly, when the normal pulse Pm8 or Pm7 is output, it isacknowledged that the power source voltage Vc shows 1.0v˜1.4V.

Also from the Table 4, since the voltage range capable of driving themotor of the high speed pulse Pf4 in a case of the load being provided,is 0.9˜1.7V, the motor may also be driven by the high speed pulse Pf4.

As explained above, since both of the normal pulse Pm and the high speedpulse Pf are the pulses which can drive the identical second steppingmotor 406-3, when a load is provided, the drive voltage of both pulses,the normal pulse Pm and the high speed pulse Pf, are increased in thesame way.

Since a relative relationship in the voltage between the normal pulse Pmand the high speed pulse Pf is not changed, the high speed pulse Pf canbe selected with respect to the normal pulse Pm under the same conditionas used in a case in which no load is provided regardless of existenceof the load.

Next, the operation of the above-noted circuits will be described.

The operation of the first stepping motor 406-1 which drives the secondhand 515, the first normal pulse generating circuit for the purpose ofsupplying a normal pulse Ps to the first stepping motor 406-1, the firstnormal pulse selection circuit 611, the fist load compensation controlcircuit 620 the second-hand drive control circuit 621, and the firstdrive circuit 407-1 is the same as described from the prior art, withreference to FIG. 5, and will therefore not be described again.

The electric energy generated by the solar cell 401 is stored in theelectrical double-layer capacitor 570. The watch circuit 402 takes itspower from this electrical double-layer capacitor 570, and is driven bythe power supply voltage Vc. When the withstand voltage of 3.0 V of theelectrical double-layer capacitor 570 is reached, a discharge circuit(not shown in the drawing) operates so that the voltage does not exceed3.0 V.

When the voltage of the electrical double-layer capacitor 570 fallsbelow 1.0 V, the judgment is made that the charging is insufficient, andtimekeeping is stopped as a notification that the charging isinsufficient. The first stepping motor 406-1, the second stepping motor406-3, and the third stepping motor 406-2 are driven when the powersupply voltage Vc is in the range 1 V to 3 V.

First, the circuit operation related to the drive of the third steppingmotor 406-2, which drives the chronograph hand 835, will be described.The third high-speed pulse generation circuit 605 generates thehigh-speed pulses Pc1 to Pc8, to be described later, based on a signalof the frequency divider circuit 404, and supplies these to the thirdhigh-speed pulse selection circuit 615.

The third high-speed pulse selection circuit 615 is controlled by thefirst load compensation control circuit 620, and selects one of thehigh-speed pulses, according to a method to be described later, andsupplies this pulse to the chronograph hand drive control circuit 624.The chronograph hand control circuit 624 supplies the high-speed pulsePc to the third drive circuit 407-2, in accordance with chronographinformation for timekeeping from the time-keeping control circuit 650.

The third drive circuit 407-2 drives the third stepping motor 407-2 bymeans of this high-speed pulse Pc.

The shape of the high-speed pulse Pc and the method of selection aredescribed in detail below.

TABLE 2 High speed pulse Pc Pulse Width and Drivable Voltage RangesHigh-speed Pulse Pulse Width Driving Voltage Range Pc1 3.0 ms 2.0 to 3.8V Pc2 3.2 ms 1.8 to 3.3 V Pc3 3.4 ms 1.6 to 2.8 V Pc4 3.6 ms 1.4 to 2.5V Pc5 3.8 ms 1.2 to 2.2 V Pc6 4.0 ms 1.0 to 1.9 V Pc7 4.2 ms 0.9 to 1.6V Pc8 4.4 ms 0.8 to 1.4 V

Table 2 shows the widths of the pulses generated by the third high-speedpulse generation circuit 605 and the range of voltages for each pulsewidth over which normal drive is possible. The high-speed pulses Pc1 toPc8 each have the driving voltage range as shown in Table 2, so that ifthe power supply voltage Vc goes outside the range, it is not possibleto drive the third stepping motor 407-2.

For example, the range of driving voltage for the high-speed pulse Pc4,which has a width of 3.6 ms, is 1.4 V to 2.5 V. Therefore if the powersupply voltage Vc is within this range of 1.4 V to 2.5 V, it is possibleto drive the third stepping motor 406-2 with the high-speed pulse Pc4.If, however, the power supply voltage Vc is less than 1.4V, because thevoltage is excessively low, it is not possible to drive the thirdstepping motor 406-2 with the high-speed pulse Pc4, and the kept timewill be disturbed. On the other hand, if the power supply voltage Vcexceeds 2.5V, the third stepping motor 406-2 will overrun, so that it isnot possible to drive the third stepping motor 406-2 with the high-speedpulse Pc4, resulting again in disturbance of the kept time. Thus, forthe purpose of driving the third stepping motor 406-2, it is neccessaryto select a proper high-speed pulse Pc.

Furthermore, it is normal to have set the high-speed pulse Pc(n) so thatit appropriately corresponds to the normal pulse Ps(n), the settingbeing made so that a voltage value that is at the appropriate center ofthe driving voltage range of the high-speed pulse Pc(n) is the minimumdriving voltage of the normal pulse Ps(n). For example, the minimumdriving voltage range of the high-speed pulse Pc6 is 1.0 to 1.9 V, whichhas a center value that is close to the minimum diving voltage, 1.4 V ofthe normal pulse Ps6.

The fist stepping motor 406-1 is provided for the purpose of driving thesecond hand 815 and, as described earlier, drives the second handnormally in any of the modes. That is, it is driven one time each 1second by a normal pulse Ps, and is subject to multistage loadcompensation operation. Therefore, the first load compensation controlsection 620 controls the first normal pulse selection circuit 611 sothat it selects the smallest normal pulse Ps that can drive the firststepping motor 406-1. By doing this, it is possible to know, by means ofthe type of normal pulse Ps output at a given time, the approximatepower supply voltage Vc. It is then sufficient to select a high-speedpulse Pc having a driving voltage range, the minimum driving voltage ofwhich is drivable by the minimum driving voltage of that normal pulsePs.

For example, from Table 1 the minimum driving voltage of the normalpulse Ps8 is 1.0 V, and the minimum driving voltage of the normal pulsePs7 is 1.2 V. Then, when the normal pulse Ps8 is output, it is possibleto know that the power supply voltage Vc is in the range 1.0 V to 1.2 V.From Table 2 the driving voltage stage of the high-speed pulse Pc8 is0.8 to 1.4 V. Thus, when the first stepping motor 406-1 is being drivenby the normal pulse Ps8, if the third stepping motor 406-2 is driven bythe high-speed pulse Pc8, sufficient drive is possible, even consideringvariation between components. From Table 1 the minimum driving voltageof the normal pulse Ps7 is 1.2 V and the minimum driving voltage of thenormal pulse Ps6 is 1.4 V.

Thus, when the normal pulse Ps7 is being output, it is possible to knowthat the power supply voltage Vc is in the range 1.2 V to 1.4 V.Therefore, the third stepping motor 406-2 can be driven by thehigh-speed pulse Pc7, which has a driving voltage range of 0.9 to 1.6 V.In a similar manner, for the normal pulses Ps6 to Ps1, drive of thethird stepping motor 406-2 can be done by the corresponding high-speedpulses Pc6 to Pc1.

The information with regard to which normal pulse of the normal pulsesPs1 to Ps8 is currently being output by the first normal pulse selectioncircuit 611 is output in the form of the signal S. Therefore, the firstload compensation control circuit 620 can recognize that the firstnormal pulse selection circuit 611 is currently outputting the normalpulse Ps(n). Then it is sufficient for the first load compensationcontrol circuit 620 to control the third high-speed pulse selectioncircuit 615 so that it selects the high-speed pulse Pc(n) thatcorresponds to this normal pulse Ps(n). For example, if the first normalpulse selection circuit 611 is selectively outputting the normal pulsePs2, control would be performed so that the third high-speed pulseselection circuit 615 selects the high-speed pulse Pc2.

Next, the switching of the high-speed pulse Ps(n) will be described.When the power supply voltage Vc drops so that drive of the firststepping motor 406-1 is not possible with the normal pulse Ps(n), thejudgment is made by the first detection circuit 630 that rotation wasnot possible, and by means of this judgment result the first loadcompensation circuit 620 controls the first normal pulse selectioncircuit 611 so as to output a compensation pulse Psh and also so as toswitch the next normal pulse Ps to the next larger normal pulse Ps(n+1).

In addition, when the first load compensation control circuit 620receives the judgment results from the first detection circuit 630 thatrotation was not possible, it controls the third high-speed pulseselection circuit 615 so as to switch from the high-speed pulse Pc(n) tothe next larger high-speed pulse Pc(n+1). When the normal pulse Ps(n) isoutput 100 times, the first load compensation control circuit 620controls the first normal pulse selection circuit 611 so as to outputthe next smaller normal pulse, Ps(n−1).

However, the drive capacity of the next smaller normal pulse Ps(n−1) issmall so that there are cases in which drive of the first stepping motor406-1 is not possible. In such a case, it is possible that drive of thethird stepping motor 406-2 is not possible even if a switch is made fromthe high-speed pulse Pc(n) to the high-speed pulse Pc(n−1). Inconsideration of this possibility, the switching of the high-speed pulsePc(n) being output by the third high-speed pulse selection circuit 615to the next smaller high-speed pulse Pc(n−1) is made after succeeding todrive the first stepping motor 406-1 with the next smaller normal pulsePs(n−1).

The above operation will be described in further detail, makingreference to a drawing. FIG. 18 is a block diagram of the first loadcompensation control circuit 620 and the surrounding area. In FIG. 18,the reference numeral 714a denotes a 100-base counter, 714b is a firstrank-up circuit, 714c is a first rank-down circuit, and 714d is a thirdrank-down control circuit. The first detection circuit 630 makes ajudgment as to whether or not the normal pulse Ps was able to drive thefirst stepping motor 406-1 and, outputting to the first loadcompensation control circuit 620 the signal Y1 if drive was possible andthe signal N1 if drive was not possible.

The signal Y1 is input to the 100-base counter 714a within the firstload compensation control circuit 620. The 100-base counter 714a is acounter which counts whether or not drive was possible 100 times withthe same normal pulse Power supply, this counter outputting the signalCU to the first rank-down circuit 714c when the signal Y1 is input 100times continuously.

The first rank-down counter 714c also has input to it the signal S,which indicates the size of the normal pulse Power supply being outputfrom the fist normal pulse selection circuit 611. When the CU signal isinput, the first rank-down counter 714c outputs the signal D1 to controlthe first normal pulse selection circuit 611 so as to switch the normalpulse Ps to the next smaller pulse Ps. Note that if the signal N1 isinput to the R terminal of the 100-base counter 714a before the 100th Ysignal, the 100-base counter 714a will be reset, this causing thecounting of the Y1 signal to start anew. The signal N1 is also input tothe first rank-up counter 714b. The first rank-up counter 714b has inputto it the S signal which indicates the size of the normal pulse Ps whichis being output from the first normal pulse selection circuit 611. Whenthe N1 signal is input, the first rank-up counter 714b outputs the U1signal to control the first normal pulse selection circuit 611 so as toswitch selection from the normal pulse Ps to the next larger normalpulse P.

When the CU signal is not being input to the third rank-down controlcircuit 714d, the third rank-down control circuit 714d controls thethird high-speed pulse selection circuit 615 so as to select thehigh-speed pulse Pc which corresponds to the size of normal pulse Ps asindicated by the signal S which is output from the first normal pulseselection circuit 611. In this case, the high-speed pulse Pc(n) whichcorresponds to the normal pulse Ps(n) which is currently selected isselected. For example, in the case in which the first stepping motor406-1 is being driven by the normal pulse Ps(n), the first detectioncircuit 630 outputs the signal Y1. By means of this signal Y1, asdescribe above, the first normal pulse selection circuit 611 selects thenormal pulse Ps(n).

Additionally, although this signal Y1 is given to the third rank-downcontrol circuit 714d, unless this is the 100th time the CU signal is notoutput from the 100-base counter 714a. In this condition, the thirdrank-down control circuit 714d controls the third high-speed pulseselection circuit 615 so as to select the high-speed pulse Pc(n) whichcorresponds to the signal S, which indicates the size of the normalpulse Ps(n) being output from the first normal pulse selection circuit611. Therefore, the normal pulse Ps(n) and high-speed pulse Pc(n) areselected as a corresponding pair. In the case in which it was notpossible to drive the first stepping motor 406-1 with the normal pulsePs(n), the first detection circuit 630 outputs the signal N1. The signalN1 causes the first normal pulse selection circuit 611 to select thenext larger normal pulse Ps(n+1). Additionally, the fact that a switchhas been made by the first normal pulse selection circuit 611 to thenext larger normal pulse Ps(n+1) is indicated to the third rank-downcontrol circuit 714d by the signal S. When this is done, the thirdrank-down control circuit 714d controls the third high-speed pulseselection circuit 615 so as to select the high-speed pulse Pc(n+1) whichcorresponds to the S signal that indicates the size of the normal pulsePs(n+1) being output from the first normal pulse selection circuit 611.Therefore, the normal pulse Ps(n+1) and high-speed pulse Pc(n+1) areselected as a corresponding pair.

When the CU signal is output from the 100-base counter 714a, the thirdrank-down control circuit 714d controls the third high-speed pulseselection circuit 615 so as to select the same high-speed pulse Pc aslast time, it ignoring the signal S which indicates the size of thenormal pulse Ps being output from the first normal pulse selectioncircuit 611 and not performing switching of the high-speed pulse Pc. Forexample, in the case in which the first normal pulse selection circuit611 is selecting the normal pulse Ps(n), by the output of the S signalby the first normal pulse selection circuit 611, the normal pulse signalbeing output is indicated. By means of this signal S, the thirdrank-down control circuit 714d selects the high-speed pulse Pc(n). Thenif it is possible to drive the first stepping motor 406-1 100 times withthe normal pulse Ps(n), the signal Y1 is output from the first detectioncircuit 630, and the CU signal is output from the 100-base counter 714a.By means of this CU signal, the first rank-down counter 714c outputs thesignal D1 to control the first normal pulse selection circuit 611 so asto select the normal pulse Ps(n−1). The fact that the first normal pulseselection circuit 611 is selecting the normal pulse Ps(n−1) is indicatedby the output of the S signal.

Although this S signal is also given to the third rank-down controlcircuit, the CU signal is being output from the 100-base counter 714a,so that regardless of the S signal the third rank-down control circuit714d controls the third high-speed pulse selection circuit 615 so as toselect the same high-speed pulse Pc(n) as last time. Therefore, afterthe same normal pulse Ps(n) is output 100 times, even if a switch ismade to the next smaller normal pulse Ps(n−1), the third high-speedpulse selection circuit 615 still selects the some high-speed pulsePc(n). Then, the next time the first stepping motor 406-1 is driven bythe normal pulse Ps(n−1), and if drive is possible with the normal pulsePs(n−1), the Y1 signal is output from the first detection circuit 630.When this Y1 is input to the third rank-down control circuit 714d, itcontrols the third high-speed pulse selection circuit 615 so as toswitch selection of the high-speed pulse Pc to the high-speed pulsePc(n−1) which corresponds to the S signal output at that time. In thecase in which drive was not possible with the normal pulse Ps(n−1), theN1 signal from the first detection circuit 630 is input to the firstrank-up circuit 714b. The first rank-up circuit 714b controls the firstnormal pulse selection circuit 611 so as to select the normal pulsePs(n) which is one larger than the normal pulse Ps(n−1). The fact thatthe normal pulse Ps(n) is selected is indicated by the S signal. Notethat, because the Y1 signal had been input to the third rank-downcontrol circuit 714d, the third high-speed pulse selection circuit 615is controlled to maintain selection of the high-speed pulse Pc(n). Atthe next time operation is performed by means of the S signal so as toselect the high-speed pulse Pc. By means of the above-describedoperation, even if the same normal pulse Ps is selected 100 times andthen a switch is made to the next smaller normal pulse Ps, it ispossible to select an appropriate high-speed pulse Pc.

An example will used next to explain circuit operation. In the powersupply voltage Vc is 1.7 V, as shown in Table 1, the first normal pulseselection circuit 611 selects the normal pulse Ps5, which has a minimumdrive voltage of 1.5 V. The first load compensation control circuit 620causes the third high-speed pulse selection circuit 615 to select thehigh-speed pulse Pc5. Therefore, if the chronograph is started at thispoint the third stepping motor 406-2 is driven at high speed by thehigh-speed pulse Pc5. From Table 2 the drive voltage range for thehigh-speed pulse Pc5 is 1.2 to 2.2 V, indicating that a power supplyvoltage Vc of 1.7 V can drive the third stepping motor 406-2sufficiently. When the normal pulse Ps5 is input 100 times, the firstload compensation control circuit 620 controls the first normal pulseselection circuit 611 so as to select and output the next smaller normalpulse Ps4.

Because with the normal pulse Ps4 it is not possible to drive the firststepping motor 406-2 when the power supply voltage is 1.7 V, the normalpulse Ps5 will be output the next time. However, the switching of thehigh-speed pulse Pc by the third high-speed pulse selection circuit 615is done only when drive was possible with the normal pulse Ps5. For thisreason, even if as described above a switch is made from the normalpulse Ps5 to the normal pulse Ps4, because drive is not possible withthe normal pulse Ps4, the third high-speed pulse selection circuit 615continues to select the high-speed pulse Ps5. Thus, if the chronographis started when the power supply voltage is 1.7 V, the third steppingmotor 406-2 will be driven at high speed by the appropriate high-speedpulse Ps5 at all times.

Next, the case of variation in the power supply voltage Vc will bedescribed. First, the case in which the power supply voltage drops from1.7 V will be described. The first stepping motor 406-1 is driven, asnoted above, by the normal pulse Ps5 at a voltage of 1.7 V. If the powersupply voltage gradually decreases from this point, the drive capacityof the normal pulse Ps5 becomes weak. Then, when the power supplyvoltage falls below the minimum driving voltage, 1.6 V, of the normalpulse Ps5, it is no longer possible to drive the first stepping motor406-1 with the normal pulse Ps5, and the first detection circuit 630judges that rotation was not possible.

In response to this judgment result, the first load compensation controlcircuit 620 controls the first normal pulse selection circuit 611 so asto output the compensation pulse Psh, this performing compensation driveof the first stepping motor 406-1, and causing the normal pulse Ps6 tobe selected the next time. Simultaneously with this, the first loadcompensation control circuit 620 controls the third high-speed pulseselection circuit 615 so as to switch selection of the high-speed pulsePc from the high-speed pulse Pc5 to the high-speed pulse Pc6. Therefore,if the chronograph is started at this point the third stepping motor406-2 is causes to be driven at high speed by the high-speed pulse Pc6.From Table 2 the driving voltage range for the high-speed pulse Pc6 is1.0 to 1.9 V, indicating that sufficient drive is possible of the thirdstepping motor 406-2 at a power supply voltage Vc of 1.7 V. The drop ofthe power supply voltage Vc is occurs gradually and is caused byconsumption of the electrical energy which is stored in the electricaldouble-layer capacitor, and because a rapid drop in voltage does notoccur the operation described above provides sufficient accommodationfor this voltage drop.

Next, the case of the power supply voltage increasing from 1.7 V will bedescribed. The first stepping motor 406-1 is driven by the normal pulsePs5 at the voltage of 1.7 V. If the power supply voltage Vc graduallyincreases from this value, the drive capacity with the normal pulse Ps5becomes accordingly large. The first load compensation control circuit620 controls the first normal pulse selection circuit 611 so as toselect and output the next smaller normal pulse Ps4 one time each timethe normal pulse Ps5 is output 100 times.

If the power supply voltage Vc increases so as to exceed the minimumdrive voltage of the normal pulse Ps4, which is 1.8 V, if the normalpulse Ps4 is selected at that point, the first stepping motor 406-1 isdriven by the normal pulse Ps4. The first detection circuit 630 judgesthat rotation was possible and, based on this judgment result, the firstload compensation control circuit 620 causes the third high-speed pulseselection circuit 615 to switch the high-speed pulse Pc from thehigh-speed pulse Pc5 to the high-speed pulse Pc4. Therefore, if thechronograph is started at this point, the third stepping motor 406-2 isdriven at high speed by the high-speed pulse Pc4.

From Table 2 the driving voltage range for the high-speed pulse Pc4 is1.4 to 2.5 V, indicating that sufficient drive of the third steppingmotor 406-2 is possible at a power supply voltage Vc of 1.8 V. Even ifthe power supply voltage Vc reaches a voltage at which drive is possiblewith the normal pulse Ps4, a switch is not made from the high-speedpulse Pc5 to the high-speed pulse Pc4 without waiting for at least 100seconds (100 of the normal pulses Ps).

However, the upper limit voltage of the voltage range in which drive ispossible with the high-speed pulse Pc(n) for each pulse is set to avalue that is higher than the minimum driving voltage of the nextsmaller normal pulse Ps(n−1), and in the case of the high-speed pulsePc5, drive is possible up to 2.2 V, which is higher than the minimumdriving voltage for the normal pulse Ps4, which is 1.8 V. Additionally,because the charging of the electrical double-layer capacitor 570 isdone with a solar cell 401 that does not have a very large electricenergy generating capacity, a problem related to not being able toswitch the high-speed pulse Pc immediately does not occur. In theabove-described manner, it is possible to select the high-speed pulse Pcfor proper drive of the third stepping motor 406-2.

Next, the circuit operation related to the drive of the second steppingmotor 406-3 which advances the minute hand 826 will be described. Thesecond normal pulse generation circuit 612 generates the normal pulsesPm1 to Pm8 and the compensation pulse Pmh, to be described later, basedon a signal from the frequency divider circuit 404, and supplies theseto the second normal pulse selection circuit 612. The second normalpulse selection circuit 612 is controlled by the second loadcompensation control circuit 622 so as to select on normal pulse Pm fromthe normal pulses Pm1 to Pm8, and suply this normal pulse to theminute-hand drive control circuit 623.

The second hand-speed pulse generation circuit 603 generates thehigh-speed pulses Pf1 to Pf4, to be described later, based on a signalfrom the frequency divider circuit 404, and supplies these to secondhigh-speed pulse selection circuit 613. The second high-speed pulseselection circuit 613 is controlled by the second load compensationcontrol circuit 622 so as to select one high-speed pulse Pf from thehigh-speed pulses Pf1 to Pf4 and to supply this high-speed pulse to theminute-hand drive control circuit 623. The second reverse-rotation pulsegeneration circuit 604 generates reverse-rotation pulses Pb1 to Pb4, tobe described later, based on a signal from the frequency divider circuit404, and supplies these reverse-rotation pulses to the secondreverse-rotation pulse selection circuit 614.

The second reverse-rotation pulse selection circuit 6514 is controlledby the second load compensation control circuit 622 so as to select onereverse-rotation pulse Pb from the reverse-rotation pulse Pb1 to Pb4 andto supply this reverse-rotation pulse to the minute-hand drive controlcircuit 623. The minute-hand drive control circuit 623 selects, asnecessary, the normal pulse Pm or high-speed pulse Pf orreverse-rotation pulse Pb, in accordance with the time which is kept bythe timekeeping control circuit 650, the alarm and the chronographinformation, and supplies this to the second drive circuit 407-3, thesecond drive circuit 407-3 drives the second stepping motor 407-3 bymeans of the normal pulse Pm, the high-speed pulse Pf or thereverse-rotation Pb which is supplied by the minute-hand drive controlcircuit 624.

The second detection circuit 631 makes a judgment as to whether or notdrive of the second stepping motor 406-3 was possible by the normalpulse Pm. Based on the results of the judgment by the second detectioncircuit 631, the second load compensation control circuit 622 controlsthe second normal pulse selection circuit 612.

In the case in which rotation occurred, it causes the same normal pulsePms to be output the next time. If rotation did not occur, however, itcauses output of the compensation pulse Pmh and causes output of thenext larger normal pulse the next time.

In addition, the second load compensation control circuit 622 controlsthe second high-speed pulse selection circuit 613 and the secondreverse-rotation pulse selection circuit 614 so as to select oneappropriate high-speed pulse Pf and reverse-rotation pulse Pb,respectively, from the high-speed pulses Pf1 to Pf4 and reverse-rotationpulses Pb1 to Pb4.

TABLE 6 Normal pulse, High speed pulse Pf and Reverse rotation pulse Pbto be selected Normal pulse High speed pulse Reverse rotation pulse Pm1Pf1 Pb1 Pm2 Pm3 Pf2 Pb2 Pm4 Pm5 Pf3 Pb3 Pm6 Pm7 Pf4 Pb4 Pm8

Table 6 shows a relationship between the normal pulses Pm1˜Pm8 and thehigh speed pulses Pf and reverse rotation pulses Pb to be selected atthe selection time.

Next, a method for selecting the normal pulse Pm and the high speedpulse Pf to be selected will be explained hereunder.

The second normal pulse selection circuit 612 outputs to the second loadcompensation control circuit 622 a signal M which indicates that towhich one of the pulse among the normal pulses Pm1˜Pm8, the normal pulsePm now being output corresponds.

Therefore, the second load compensation control circuit 622discriminates the normal pulse Pm which the second normal pulseselection circuit 612 now outputs. And accordingly, the second loadcompensation control circuit 622 may control the second high speed pulseselection circuit 613 to have a high speed pulse Pf corresponding to anormal pulse Pm selected.

In this selection, as shown in the Table 6, when the normal pulse Pm1 orPm2 is mentioned, the high speed pulse Pf1 should be selected to beoutput to the second high speed pulse selection circuit 613, and as thesame manner, when the normal pulse Pm3 or Pm4 is mentioned, the highspeed pulse Pf2 should be selected, when the normal pulse Pm5 or Pm6 ismentioned, the high speed pulse Pf3 should be selected and when thenormal pulse Pm7 or Pm8 is mentioned, the high speed pulse Pf4 should beselected.

Next, when the power source voltage is reduced, and thus the firststepping motor 406-1 cannot be driven by the normal pulse Pm(n), thesecond detection circuit 631 determines that the motor did not rotateand base upon this determination, the second load compensation controlcircuit 622 controls the second normal pulse selection circuit 612 tooutput a compensation drive pulse Pmh and simultaneously change thenormal pulse Pm to the normal pulse Pm (n+1) having large voltage levelone level up compared with that of the normal pulse Pm, for the nextoperation.

When the normal pulse is one of the normal pulses of Pm1, Pm3, Pm5 andPm7, the second load compensation control circuit 622 controls thesecond high speed pulse selection circuit 613 to select the same highspeed pulse Pf as selected the pervious time even when the second loadcompensation control circuit 622 receives the determination that themotor did not rotate from the second detection circuit 631.

On the other hand, when the normal pulse is one of the normal pulses ofPm2, Pm4, and Pm6, the second load compensation control circuit 622controls the second high speed pulse selection circuit 613 to change thehigh speed pulse Pf to the high speed pulse Pf having large voltagelevel one level up compared with that of the normal pulse Pf, previouslyoutput, simultaneously with the reception of the determination that themotor did not rotate from the second detection circuit 631.

Namely, when the no rotation of the motor is detected at any one of thenormal pulses of Pm1, Pm3, Pm5 and Pm7, the high speed pulse Pf1, Pf2,Pf3 and Pf4 are maintained but when the no rotation of the motor isdetected an any one of the normal pulses of Pm2, Pm4, and Pm6, the highspeed pulse Pf will be selectively changed to the next one such as thehigh speed pulse Pf1 should be changed to Pf2, the high speed pulse Pf2should be changed to Pf3, and the high speed pulse Pf3 should be changedto Pf4, respectively.

When the normal pulse Pm(n) are continuously output in successive 100times, the second load compensation control circuit 622 controls thesecond normal pulse selection circuit 612 to switch a normal pulse Pm toa normal pulse Pm(n−1) having small voltage level one level downcompared with that of the normal pulse Pm, previously output.

When the normal pulse Pm(n) is any one of Pm3, Pm5 and Pm7, it has beenchanged to one of a normal pulse Pm2, Pm4, and Pm6, having small voltagelevel, however, when the motor could be driven by any one of the normalpulse Pm(n−1), such as Pm2, Pm4, and Pm6, the high speed pulse Pf2, Pf3,and Pf4 is changed to Pf1, Pf2 and Pf3, respectively.

But when the motor could not rotate with the normal pulse Pm2, Pm4, andPm6, having one level down small voltage level, the high speed pulsePf2, Pf3 and Pf4 should be maintained.

The explanation will be made with reference to an example.

When the date panel 881 is not provided, when the power source voltageVc is 1.6V, the most suitable normal pulse Pm is the normal pulse Pm5having the minimum drive voltage 1.5, referring to the Table 3.

And in the normal timekeeping mode, the second load compensation controlcircuit 622 controls the second normal pulse selection circuit 612 tooutput the normal pulse Pm5, and further, as shown in Table 6, controlsthe second high speed pulse selection circuit 613 to output a high speedpulse Pf3.

Therefore, at this stage, when the normal timekeeping mode is changed toan alarm mode, the second stepping motor 406-3 is driven with the highspeed pulse Pf3.

As seen from the Table 4, the voltage range capable of driving the motorof the high speed pulse Pf5 is 1.0˜2.2V and thus the power sourcevoltage of 1.6V can sufficiently drive the second stepping motor 406-3.

On the other hand, in the normal timekeeping mode, when the normal pulsePm5 is continuously output in successive 100 times, the second loadcompensation control circuit 622 controls the second normal pulseselection circuit 612 to output a normal pulse Pm4 having a voltage thelevel of which is one level down compared with that of the pulsepreviously output.

Seeing from the Table 3, the minimum drive voltage of the normal pulsePm4 is 1.7V and thus the power source voltage of 1.6V cannot drive thesecond stepping motor 406-3. And thus the second load compensationcontrol circuit 622 controls the second normal pulse selection circuit612 again to selectively output the normal pulse Pm5 from the nextoperation period.

However, the change of the high speed pulse Pf of the second high pulseselection circuit 613 can be carried out only when the second steppingmotor 406-3 can be driven by the normal pulse Pm4, and thus when thesecond stepping motor 406-3 can not be driven by the normal pulse Pm4,the second high pulse selection circuit 613 is still selecting the highspeed pulse Pf3.

Therefore, when the normal timekeeping mode is changed to the alarm modewith the power source voltage of 1.6V, the second stepping motor 406-3can always be driven by a suitable high speed pulse Pf3, with highspeed.

Next, the case in which the power source voltage Vc is varied will beexplained hereunder.

First, the case in when the power source voltage Vc is reduced from 1.6Vwill be explained.

Under the power source voltage Vc of 1.6V, the second stepping motor406-3 is driven by the normal pulse Pm5 in the normal timekeeping modeand the second load compensation control circuit 622 controls the secondhigh pulse selection circuit 613 to select the high speed pulse Pf3.

From this point, when the power source voltage Vc is reduced gradually,the driving power of the normal pulse Pm5 becomes weak and when thepower source voltage Vc reduces below the minimum drive voltage of 1.5Vof the normal pulse Pm5, the second stepping motor 406-3 cannot bedriven by the normal pulse Pm5,

Therefore, the second detection circuit 631 determines that the motordid not rotate. And then the second load compensation control circuit622 controls the second normal pulse selection circuit 612 in responseto this determination, to output the compensation drive pulse Pmh so asto compensate to drive the second stepping motor 406-3 and toselectively output a normal pulse Pm6, from the next operation.

In this case, although, the normal pulse Pm5 is changed to the normalpulse Pm6, the second load compensation control circuit 622 does notcontrol the second normal pulse selection circuit 612 to change the highspeed pulse Pf and still to maintain the high speed pulse Pf3.

Therefore, at this stage, when the normal timekeeping mode is changed tothe alarm mode, the second stepping motor 406-3 is driven by the highspeed pulse Pf3 with high rotational speed.

Referring to the Table 4, the voltage range capable of driving the motorof the high speed pulse Pf5 is 1.0˜2.2V and thus the power sourcevoltage Vc of 1.5V can sufficiently drive the second stepping motor406-3.

Further, when the power source voltage Vc reduces below the minimumdrive voltage of 1.3V of the normal pulse Pm6, the second stepping motor406-3 cannot be driven by the normal pulse Pm6, and thus the seconddetection circuit 631 determines that the motor did not rotate.

In response to this determination, the second load compensation controlcircuit 622 control the second normal pulse selection circuit 612 tooutput the compensation drive pulse Pmh so as to compensate the drive ofthe second stepping motor 406-3, and thereafter to output the normalpulse Pm7 from the next operation period.

At the same time, the second load compensation control circuit 622control the second high speed pulse selection circuit 613 to selectivelychange the high speed pulse Pf3 to the high speed pulse Pf4.

Accordingly, in this stage, when the normal timekeeping mode is changedto the alarm mode, the second stepping motor 406-3 can be driven by thehigh speed pulse Pf4 with high rotational speed.

As seen from the Table 4, the voltage range capable of driving the motorof the high speed pulse Pf4 is 0.9˜1.7V and thus the power sourcevoltage Vc of 1.3V can sufficiently drive the second stepping motors406-3.

Next, the case when the power source voltage Vc is increased from 1.6V,will be explained hereunder.

The second stepping motor 406-3 is driven by the normal pulse Pm5 underthe power source voltage Vc of 1.6V, when the normal timekeeping mode isused. And the second load compensation control circuit 622 controls thesecond high speed pulse selection circuit 613 to select the normal pulsePm3.

From this point, when the power source voltage Vc is increasedgradually, the driving power of the normal pulse Pm5 becomes large.

On the other hand, the second load compensation control circuit 622controls the second normal pulse selection circuit 612 so as toselectively output a normal pulse Pm4 having a voltage level one levelsmaller than that of the normal pulse Pm5 once in 100 successiveoutputs.

And when the power source voltage Vc exceeds the minimum voltage levelof 1.7v of the normal pulse Pm4 and the normal pulse Pm4 is selectivelyoutput, the second stepping motore 406-3 is driven by the normal pulsePm4.

At this time, the second load compensation control circuit 622 controlsthe second high speed pulse selection circuit 613 to change the highspeed pulse Pf 3 to Pf2 and selectively output the high speed pulse Pf2.

Accordingly, at this stage, when the normal timekeeping mode is changedto the alarm mode, the second stepping motor 406-3 is driven by the highspeed pulse Pf4.

Referring to the Table 4, the voltage range capable of driving the motorof the high speed pulse Pf2 is 1.4˜2.8V and thus the power sourcevoltage Vc of 1.7V can sufficiently drive the second stepping motor406-3.

Further, when the power source voltage Vc is increased to 1.9V, andafter when the normal pulse Pm3 is output successively 100 times, thesecond load compensation control circuit 622 controls the second normalpulse selection circuit 612 so as to output the normal pulse Pm3 havingthe voltage level which is one level smaller than that of the normalpulse output previously.

Therefore, the second stepping motor 406-3 can be driven by the normalpulse Pm3 having the minimum voltage level of 1.9V.

At this stage, the second load compensation control circuit 622 does notcontrol the second normal pulse selection circuit 612 to change theselection of the high speed pulse Pf and to maintain the high speedpulse Pf2.

Accordingly, in this stage, when the normal timekeeping mode is changedto the alarm mode, the second stepping motor 406-3 can be driven by thehigh speed pulse Pf2 with high rotational speed.

As seen from the Table 4, the voltage range capable of driving the motorof the high speed pulse Pf2 is 1.4˜2.8V and thus the power sourcevoltage Vc of 1.9V can sufficiently drive the second stepping motor406-3.

The explanation was made about the high speed rotation, the sameoperation can be similarly applied to the reverse rotational operation.

Namely, the second load compensation control circuit 622 controls thesecond reverse rotation pulse selection circuit 614 as the same manneras to control the second high speed pulse selection circuit 613.

And the reverse rotation pulse Pb which can select the second reverserotation pulse selection circuit 614 is selected so that the reverserotation pulse has the same the voltage range capable of driving themotor as the high speed pulse Pf1 has.

Namely, when the high speed pulse Pf1 is selected the reverse rotationpulse Pb1 is selected and as the same manner, when the high speed pulsePf2 is selected, the reverse rotation pulse Pb2 is selected and when thehigh speed pulse Pf3 is selected, the reverse rotation pulse Pb3 isselected and further when the high speed pulse Pf4 is selected, thereverse rotation pulse Pb4 is selected.

However, in a case may be, there is a case in which the second steppingmotor 406-3 cannot be driven by the normal pulse Pm for a long time.

For example, such case corresponds to any one of the case when theoperation of correction of the time has been carried out for a long timeunder an alarm mode, or when the alarm mode is unduly remained and aminute hand 825 or hour hand 826 has been stopped for a long timedisplaying an alarm setting time.

In these cases, a certain amount of time had passed since the secondstepping motor 406-3 had been driven by the last normal pulse Pm,therefore, the driving condition thereof may be changed due to thevoltage of the electric two-layered condenser 570 or the like.

In this case, when the high speed pulse Pf of the reverse rotation pulsePb is selected and output by the normal pulse Pm used previous period,the pulse may falls outside of the voltage range capable of driving themotor thereof so that the erroneous operation will occur to cause thewatch to show incorrect time.

In order to avoid this problem, the minute hand drive control circuit623 is controlled by the erroneous operation preventing circuit 655 andthus when the second stepping motor 406-3 has not been driven by thenormal pulse Pm, for a long time, the driving operation by high speedrotation or reverse rotation is tentatively stopped and the drivingoperation is switched to multi-load compensation operation by the normalpulse Pm with 16 Hz which is the maximum speed under which the normalpulse Pm can be driven in the multi-load compensation operation.

Accordingly, under this operation mode, a suitable normal pulse Pm for acurrent driving condition is selected and a suitable high speed pulse Pfor a suitable reverse rotation pulse Pb is again selected by the normalpulse Pm to thereby the driving operation can be restarted.

The circuit operation thereabout will be explained hereunder.

At every time when a one pulse of either the high speed pulse Pf or thereverse rotation pulse Pb, i.e., non-normal pulse, is output from theminute hand drive control circuit 623, a signal H is output.

The erroneous operation preventing circuit 655 is counting the number ofsignal H generated from the minute hand drive control circuit 623. Andwhen the number thereof reaches at 2000, the erroneous operationpreventing circuit 655 controls the the minute hand drive controlcircuit 623 to stop the generation of any one of the high speed pulse Pfor the reverse rotation pulse Pb and select and output the normal pulsePm the frequency thereof being 16 Hz and which is output from the secondnormal pulse selection circuit 612, instead.

And simultaneously, the erroneous operation preventing circuit 655controls the second load compensation control circuit 622 to have secondnormal pulse selection circuit 612 selected the normal pulse Pm4 havinga middle size among the normal pulses of Pm1˜Pm8.

Further, the erroneous operation preventing circuit 655 controls thesecond load compensation control circuit 622 so that as mentioned above,in normal time, when the normal pulse Pm4 can drive the motor insuccessive 100 times, the normal pulse Pm4 is changed to the normalpulse Pm3 having a voltage one level below that of the normal pulse Pm4,but in this case, when once the normal pulse Pm4 can drive the motor,the pulse Pm4 is just change to the normal pulse Pm2 having a voltagelevel two levels below the that of the normal pulse Pm4 and output same.

On the other hand, when the normal pulse Pm2 can not drive the motor, itis considered that the normal pulse Pm4 or Pm3 would be a suitablenormal pulse Pm under this circumstance and thus as shown in the Table6, the high speed pulse Pf2 and the reverse rotation pulse Pb2 aresuitable high speed pulse Pf and reverse rotation pulse Pb under thesecircumstance.

Therefore, the erroneous operation preventing circuit 655 controls theminute hand drive control circuit 623 to restart to drive the motor withthe high speed pulse Pf2 or the reverse rotation pulse Pb2.

And when the motor can be driven by the normal pulse Pm2, it isconsidered that the normal pulse Pm2 or Pm1 would be a suitable normalpulse Pm under this circumstance and thus as shown in the Table 6, thehigh speed pulse Pf1 and the reverse rotation pulse Pb1 are suitablehigh speed pulse Pf and reverse rotation pulse Pb under thesecircumstance.

Accordingly, the erroneous operation preventing circuit 655 controls theminute hand drive control circuit 623 to restart to drive the motor withthe high speed pulse Pf1 or the reverse rotation pulse Pb1.

And when the normal pulse Pm4 which was first output, cannot drive themotor, the compensation drive pulse Pmh is output so as compensatelydrive the motor and then the normal pulse Pm6 having voltage two levelsup compared with the same of the normal pulse generated previously.

When the motor can be driven by the normal pulse Pm6, it is consideredthat the normal pulse Pm6 or Pm5 would be a suitable normal pulse Pmunder this circumstance and thus as shown in the Table 6, the high speedpulse Pf3 and the reverse rotation pulse Pb3 are suitable high speedpulse Pf and reverse rotation pulse Pb under these circumstance.

Accordingly, the erroneous operation preventing circuit 655 controls theminute hand drive control circuit 623 to restart to drive the motor withthe high speed pulse Pf3 or the reverse rotation pulse Pb3.

And when the normal pulse Pm6 cannot drive the motor, it is consideredthat the normal pulse Pm7 or Pm8 would be a suitable normal pulse Pmunder this circumstance and thus as shown in the Table 6, the high speedpulse Pf4 and the reverse rotation pulse Pb4 are suitable high speedpulse Pf and reverse rotation pulse Pb under these circumstance.

Accordingly, the erroneous operation preventing circuit 655 controls theminute hand drive control circuit 623 to restart to drive the motor withthe high speed pule Pf4 or the reverse rotation pulse Pb4.

In this circumstance, number of the high speed pulse Pf is reduced tothe extent that the motor is driven by the normal pulse Pm and thenumber of the reverse rotation pulse Pb is increased to the extent thatthe motor is driven by the normal pulse Pm, so that the timekeepingoperation can be maintain in a correct condition.

On the other hand, at every when one pulse of the normal pulse Pm isoutput, a signal J is output.

The erroneous operation preventing circuit 655 monitors time durationmeasured from the time when the J signal was output to the time when thenext J signal will be output and when such time duration in that nosignal J is output, exceeds one hour, the erroneous operation preventingcircuit 655 controls the minute hand drive control circuit 623 and thesecond load compensation control circuit 622 to stop the drive of themotor by the high speed pulse Pf and reverse rotation pulse Pb and toselect a suitable normal pulse Pm through the multi-load compensationoperation. And further, after when the high speed pulse Pf and reverserotation pulse Pb are selected, the driving operation will be restartedwith such the high speed pulse Pf and reverse rotation pulse Pb.

As explained above, the operations as mentioned above, can effectivelycompensate the reduction in voltage due to the continuous drivingoperation by the high speed pulse Pf and reverse rotation pulse Pb ordue to the discharge of the electric two-layered condenser 570 during atime in that no normal pulse Pm is output for long time.

In the examples as mentioned above, the second stepping motor 406-3 andthe first stepping motor 406-1 are provided independently though, thecontrolling method of the second stepping motor 406-3 is the same manneras used in the first stepping motor 406-1.

On the other hand, in the present invention, both motors can be combinedinto one motor to control it under the same method.

As explained above, even in an electric watch the voltage of the powersource can be varied, high speed rotation and reverse rotation can becarried out by taking a multi-load compensation operation in that anon-normal pulse having a voltage range capable of driving the motorcorresponding to a minimum voltage level of the selected normal pulse,is selectively output.

Accordingly, even in an electric watch, such as a solar watch, in whicha power source voltage of which is easily varied, an alarm function ofchronographical function can be installed therein and thus the width ofthe commercial goods can be expanded.

Namely, even a third stepping motor 406-2 which is usually stopped andcannot operate the multi-load compensation operation so that the drivingcondition thereof being indefinite, the driving condition thereof can beestimated by a normal pulse used in the other stepping motor alwaysdriven by carrying out the multi-load compensation operation such as thefirst stepping motor 406-1 and thus it can be accurately driven by anon-normal pulse which was determined as a suitable one.

Accordingly, a solar battery driven watch having a high speed rotationalfunction such as a chronographical function can be provided.

More over, as in the second stepping motor 406-3, when a non-normalpulse is determined by a normal pulse used in the same stepping motor,not only a voltage condition but also a load condition are took intoaccount, and thus this conception can be applied to a stepping motor inwhich load can in varied.

Further, the present invention can provide a solar battery driven watchin which the hour/minute hand having a calender load, can be accuratelydriven with high speed rotation or reverse rotation and also providedwith an alarm function.

In these embodiments as mentioned above, although, the explanation hadbeen made to an electronic watch having hands working by re-chargeablebattery which can show a remarkable effect thereof, it is apparent thatthe present invention can be applied to an electronic watch having handsworking by normal mercury battery or lithium battery as a power sourceand the same effect as explained in the above-mentioned embodiments canobtained.

1. An electronic watch comprising: a power supply; an oscillatorcircuit; means for generating a drive pulse; a drive motor which drivesa hand, in response to a drive pulse output from said drive pulsegenerating means; drive circuit means for controlling drive of saidmotor; means for controlling said drive circuit means; and means,connected to said drive circuit control means, for detecting a controlcondition in said drive circuit control means, said control conditiondetection means being provided with, a first non-proper conditiondetecting means for detecting a non-proper condition of said drivemotor, which sense an occurrence of a condition in which proper drive ofsaid drive motor is not possible under a prescribed condition, a firstinstructing means for instructing a change of a control mode whichinstructs said drive circuit control means to change the control modethat is currently being executed, in response to said detection signaloutput from said first non-proper condition detecting means, a secondnon-proper condition detecting means for detecting a non-propercondition of said drive motor, which sense an occurrence of a conditionin which proper drive of said drive motor is not possible under aprescribed condition even after the control mode had been changed for apredetermined period, and a second instructing means for instructing achange of a control mode which instructs said drive circuit controlmeans to change the currently executed control mode instructed by saidsecond non-proper condition detecting means, to the original controlmode when a non-proper condition of said drive motor has been detectedwithin said predetermined period, which instructs said drive circuitcontrol means to change the currently executed control mode instructedby said second non-proper condition detecting means, to further separatecontrol mode when non-proper condition of said drive motor has beendetected within said predetermined period.
 2. An electronic watchaccording to claim 1, wherein said drive pulse generation meanscomprises a group of drive pulse generation circuits which generate aplurality of types of drive pulses, said group including a normalhand-drive pulse generation circuit which generates a drive pulse fornormal hand drive based on a prescribed frequency generated from saidoscillator circuit.
 3. An electronic watch according to claim 1, whereinaid control mode change instructing means, in response to a detectionsignal of said non-proper condition detection means, outputs aninstruction to said drive circuit control means so as to stop thecontrol mode which is currently being executed.
 4. An electronic watchaccording to claim 1, wherein said control mode change instructingmeans, in response to a detection signal of said non-proper conditiondetection means, outputs an instruction to said drive circuit controlmeans so as to change control mode which is currently being executed toanother control mode.
 5. An electronic watch according to claim 1,wherein said control mode changing instructing means, in response to adetection signal of said non-proper condition detection means, outputsan instruction to said drive circuit control means so as to replace adrive pulse used in the control mode currently being executed to aanother drive pulse.
 6. An electronic watch comprising: a power supply;an oscillator circuit; means for generating a drive pulse; a drive motorwhich drives a hand, in response to a drive pulse output from said drivepulse generating means; drive circuit means for controlling drive ofsaid motor; means for controlling said drive circuit means; and means,connected to said drive circuit control means, for detecting a controlcondition in said drive circuit control means, said drive pulsegeneration means including at least a normal hand-drive pulse generatingcircuit, a fast-forward (high-speed) pulse generation circuit whichgenerates a fast-forward pulse in response to an operation of anexternal operating element, a reverse-rotation pulse generating circuitwhich generates a reverse-rotation pulse in response to an operation ofan external operating element, and said control condition detectionmeans being provided with means for detecting a non-proper condition,and with a control mode change instructing circuit which, in response toan output signal of said non-proper condition detection means, causes adrive output signal output from each one of said pulse generationcircuits to selectively pass, wherein in response to a discriminationsignal output from said non-proper condition detection circuit, saidmode change instructing circuit prohibits said drive circuit controlmeans from passing a reverse-rotation pulse.
 7. An electronic watchaccording to claim 6, wherein said non-proper condition detection meanscomprising a voltage level discrimination circuit that detects thevoltage level of said power supply, and said drive pulse generationmeans is provided with a low-voltage fast-forward pulse generating meansthat generates a low-voltage fast-forward pulse which has a width thatis greater than said fast-forward pulse, and wherein when said powersupply voltage is outside of a prescribed voltage range, in response toa discrimination signal output from said non-proper condition detectioncircuit, said mode change instructing circuit permits said drive circuitcontrol means to pass a reverse-rotation pulse.
 8. An electronic watchcomprising: a power supply; an oscillator circuit; means for generatinga drive pulse; a drive motor which drives a hand in response to a drivepulse output from said drive pulse generating means; drive circuit meansfor controlling drive of said motor; means for controlling said drivecircuit means; and means, connected to said drive circuit control means,for detecting a control condition in said drive circuit control means,said drive pulse generating means including at least a normal hand-drivepulse generating circuit, a compensation drive pulse generation circuit,and a fast-forward (high-speed) pulse generation circuit, said drivemotor and said motor drive circuit means comprising a first drive motorwhich is driven by said normal hand-drive pulse, a first driving circuitmeans, a second drive motor driven by high speed pulse having higherdriving speed than said normal hand drive pulse and a second drivingcircuit means, said drive circuit control means including a loadcompensation control system which detects whether or not said firstdrive motor rotated in response to a prescribed drive pulse which issupplied by said first drive circuit means and in the case in which ajudgement is made than the first drive motor did not rotate, whichsupplies a prescribed compensation drive pulse to said first drivecircuit means, thereby compensating the rotation of the first drivemotor, and said control condition circuit means being provided with anon-proper condition detection means comprising a monitor circuit whichmonitors a rotating condition of the second drive motor, and beingfurther provided with a control mode change instructing means which, inresponse to a detection signal which indicates the rotation condition ofsaid second drive motor, stops execution of the load compensation systemfor said first drive motor.
 9. An electronic watch according to claim 8,wherein in the case in which said control mode change instructing meansstops the execution of the load compensation system with respect to saidfirst drive motor by means of a detection signal from said non-propercondition detection means, said compensation drive pulse is supplied tosaid first drive motor.
 10. An electronic watch comprising: a powersupply; an oscillator circuit; means for generating a drive pulse; adrive motor which drives a hand, in response to a drive pulse outputfrom said drive pulse generating means; drive circuit means forcontrolling drive of said motor; means for controlling said drivecircuit means; and means, connected to said drive circuit control means,for detecting a control condition in said drive circuit control means,said drive pulse generating means including at least a normal hand-drivepulse generation circuit which generates a normal hand-drive pulse and anon-normal drive pulse generation circuit which generates a non-normalhand-drive pulse that differs from the normal hand-drive pulse, and alsocomprising a first drive motor which is driven by said normal hand-drivepulse, a first drive circuit means, a second drive motor which is drivenby said non-normal hand-drive pulse and a second drive circuit means,and configured so that, from said normal hand-drive pulse generationcircuit and non-normal hand-drive pulse generation circuit, a pluralityof normal hand-drive pulses and compensation pulse having mutuallydiffering drive capacities, and a plurality of non-normal hand-drivepulses and compensation pulses having mutually differing drivecapacities are individually output, said drive circuit control meansincluding a load compensation control system which detects whether ornot said first drive motor rotated in response to a prescribed drivepulse which is supplied by said first drive circuit means and in thecase in which a judgement is made that the first drive motor did notrotate, which supplies a prescribed compensation drive pulse to saidfirst drive circuit means, thereby compensating the rotation of thefirst drive motor, and said control condition detection means beingprovided with, a non-proper condition detection means which outputspredicted voltage information from said power supply voltage in saidload compensation control system, and with a control mode changeinstructing means comprising a selection circuit which, based on theinformation of said non-proper condition detection means, selects atleast one drive pulse from at least one drive pulse group of the normalhand-drive pulse group and non-normal hand-drive pulse group which areoutput from said normal hand-drive pulse generation circuit and saidnon-normal hand-drive pulse generation circuit.
 11. An electronic watchaccording to claim 10, wherein said drive circuit control means includesa loae compensation control system in which after when the rotation ofsaid first motor has been detected by changing a drive pulse for saidfirst motor was changed, a second pulse is changed.
 12. An electronicwatch according to claim 10, wherein said first drive motor and saidsecond drive motor are one and the same drive motor.
 13. An electronicwatch according to claim 10, wherein said non-normal hand-drive pulsegeneration circuit is a high-speed pulse generation circuit.
 14. Anelectronic watch according to claim 10, wherein said non-normalhand-drive pulse generation circuit is a reverse-rotation pulsegeneration circuit.
 15. An electronic watch comprising: a power supply;an oscillator circuit; means for generating a drive pulse, comprising agroup of drive pulse generation circuits which generate a plurality oftypes of drive pulses, said group including a normal hand-drive pulsegeneration circuit which generates a drive pulse for normal hand drivebased on a prescribed frequency generated from said oscillator circuit,and at least one drive pulse generation circuit selected from the groupcomprising a compensation drive pulse generation circuit, a pulsegeneration circuit for a rotation detection signal of said drive motor,a low-voltage hand-drive pulse generation circuit, a fast-forward(high-speed) pulse generation circuit, a low-voltage fast-forward pulsegeneration circuit, a reverse-rotation pulse generation circuit, and afunctional hand drive high-speed rotation pulse generation circuit; adrive motor which drives at least one of an hour/minute hand, a secondhand, or a functional hand, in response to a drive pulse output fromsaid drive pulse generating means; drive circuit means for controllingdrive of said motor; means for controlling said drive circuit means; andmeans, connected to said drive circuit control means, for detecting acontrol condition in said drive circuit control means, said controlcondition detection means being provided with, means for detecting anon-proper condition which sense on occurrence of a condition in whichproper drive of said drive motor is not possible under a prescribedcondition, and means for instructing a change of a control mode whichinstructs said drive circuit control means to change the control modethat is currently being executed, in response to said detection signaloutput from said non-proper condition detecting means.
 16. An electronicwatch according to claim 15, wherein one pulse generation circuit whichis selected from at least a normal hand-drive pulse generation circuit,a fast-forward (high-speed) pulse generation circuit, a reverse-rotationpulse generation circuit, and a functional hand drive high-speedrotation pulse generation circuit which are included in said drive pulsegeneration means further comprises individual pulse generation circuitswhich generate a plurality of types of drive pulses having mutuallydiffering drive capacities.
 17. An electronic watch according to claim15, wherein said compensation drive pulse generation means includes onepulse generation circuit selected from said normal hand-drive pulsegeneration circuit, said fast-forward (high-speed) pulse generationcircuit, said reverse-rotation pulse generation circuit, and saidfunctional hand drive high-speed rotation pulse generation circuit. 18.An electronic watch comprising: a power supply; an oscillator circuit;means for generating a drive pulse; a drive motor which drives at leastone of an hour/minute hand, a second hand, or a functional hand, inresponse to a drive pulse output from said drive pulse generating means;drive circuit means for controlling drive of said motor; means forcontrolling said drive circuit means, including a load compressioncontrol system which detects whether or not said drive motor rotated inresponse to a prescribed drive pulse supplied by said drive circuitmeans, and if a judgement is made that said drive motor did not rotate,supplies a prescribed compensation drive pulse to said drive circuitmeans, thereby compensating the rotation of said drive motor; and means,connected to said drive circuit control means, for detecting a controlcondition in said drive circuit control means, said control conditiondetection means being provided with, means for detecting a non-propercondition which sense an occurrence of a condition in which proper driveof said drive motor is not possible under a prescribed condition, andmeans for instructing a change of a control mode which instructs saiddrive circuit control means to change the control mode that is currentlybeing executed, in response to said detection signal output from saidnon-proper condition detecting means.
 19. An electronic watchcomprising: a power supply; an oscillator circuit; means for generatinga drive pulse; a drive motor which drives at least one of an hour/minutehand, a second hand, or a functional hand, in response to a drive pulseoutput from said drive pulse generating means; drive circuit means forcontrolling drive of said motor; means for controlling said drivecircuit means; and means, connected to said drive circuit control means,for detecting a control condition in said drive circuit control means,said control condition detection means being provided with, means fordetecting a non-proper condition which sense an occurrence of acondition in which proper drive of said drive motor is not possibleunder a prescribed condition, including means for detecting a voltagelevel of said power supply, and means for instructing a change of acontrol mode which instructs said drive circuit control means to changethe control mode that is currently being executed, in response to saiddetection signal output from said non-proper condition detecting means.20. An electronic watch comprising: a power supply; an oscillatorcircuit; means for generating a drive pulse; a drive motor which drivesat least one of an hour/minute hand, a second hand, or a functionalhand, in response to a drive pulse output from said drive pulsegenerating means; drive circuit means for controlling drive of saidmotor; means for controlling said drive circuit means; and means,connected to said drive circuit control means, for detecting a controlcondition in said drive circuit control means, said control conditiondetection means being provided with, means for detecting a non-propercondition which sense an occurrence of a condition in which proper driveof said drive motor is not possible under a prescribed condition,including a second motor which is positioned adjacent to said motor, andmeans for detecting a drive condition of the second motor with respectto which prescribed drive control is being executed, and means forinstructing a change of a control mode which instructs said drivecircuit control means to change the control mode that is currently beingexecuted, in response to said detection signal output from saidnon-proper condition detecting means.
 21. An electronic watchcomprising: a power supply; an oscillator circuit; means for generatinga drive pulse; a drive motor which drives at least one of an hour/minutehand, a second hand, or a functional hand, in response to a drive pulseoutput from said drive pulse generating means; drive circuit means forcontrolling drive of said motor; means for controlling said drivecircuit means; and means, connected to said drive circuit control means,for detecting a control condition in said drive circuit control means,said control condition detection means being provided with, means fordetecting a non-proper condition which sense an occurrence of acondition in which proper drive of said drive motor is not possibleunder a prescribed condition, including means for detecting a predictedvoltage level of said power supply which is recognized by a loadcompensation control system, and means for instructing a change of acontrol mode which instructs said drive circuit control means to changethe control mode that is currently being executed, in response to saiddetection signal output from said non-proper condition detecting means.22. An electronic watch comprising: a power supply, wherein an outputvoltage of said power supply changes with the passage of time; anoscillator circuit; means for generating a drive pulse; a drive motorwhich drives at least one of an hour/minute hand, a second hand, or afunctional hand, in response to a drive pulse output from said drivepulse generating means; drive circuit means for controlling drive ofsaid motor; means for controlling said drive circuit means; and means,connected to said drive circuit control means, for detecting a controlcondition in said drive circuit control means, said control conditiondetection means being provided with, means for detecting a non-propercondition which sense an occurrence of a condition in which proper driveof said drive motor is not possible under a prescribed condition, andmeans for instructing a change of a control mode which instructs saiddrive circuit control means to change the control mode that is currentlybeing executed, in response to said detection signal output from saidnon-proper condition detecting means.
 23. An electronic watch accordingto claim 22, wherein said power supply comprises one type selected froma secondary battery, and a large capacitance condenser.
 24. Anelectronic watch comprising: a power supply; an oscillator circuit; ameans for generating a drive pulse; a drive motor which drives a hand,in response to a drive pulse output from said drive pulse generatingmeans; a drive circuit for controlling drive of said drive motor; and adrive circuit controlling means for controlling said drive circuit; andsaid electronic watch further comprising: a means for detecting anon-proper condition which sense an occurrence of a condition in whichproper drive of said drive motor is not possible under a prescribedcondition; means for instructing a change of a control mode whichinstructs said drive circuit controlling means to change the controlmode that is currently being executed, in response to a detection signaloutput from said non-proper condition detecting means, wherein saidmeans for instructing a change of a control mode instructs said drivecircuit controlling means for controlling said drive circuit means toreturn to the original controlling mode which had been used before thecurrent controlling mode was instituted, after said control mode hadbeen changed and no such detection signal has been output from saidnon-proper condition detecting means; wherein said non-proper conditiondetecting means is a means for detecting electric power which outputs adetecting signal in response to a detection of reduction in powercondition in said power supply; and wherein said drive pulse generationmeans is provided with a fast-forward (high-speed) pulse generationcircuit which generates a fast-forward pulse and a low-voltagefast-forward pulse generating means that generates a low-voltagefast-forward pulse which has a pulse width that is greater than that ofsaid fast-forward pulse, and wherein said drive circuit controllingmeans permits passage of said low-voltage fast-forward pulse, inresponse to said detection signal output from said electric powerdetecting means.
 25. An electronic watch according to claim 24, whereinsaid non-proper condition detecting means further comprising a firstnon-proper condition detecting means for detecting a non-propercondition of said drive motor, which sense an occurrence of a conditionin which proper drive of said drive motor is not possible under aprescribed condition, and a second non-proper condition detecting meansfor detecting a non-proper condition of said drive motor which senses anoccurrence of a condition in which proper drive of said drive motor isnot possible under a prescribed condition even after the control modehad been changed for a predetermined period; and said control modechange instructing means further comprising a first instructing meansfor instructing a change of a control mode which instructs said drivecircuit control means to change the control mode that is currently beingexecuted, in response to said detection signal output from said firstnon-proper condition detecting means, and a second instructing means forinstructing a change of a control mode which instructs said drivecircuit control means to change the currently executed control modeinstructed by said second non-proper condition detecting means to theoriginal control mode when a non-proper condition of said drive motorhas not been detected within said predetermined period, and whichinstructs said drive circuit control means to change the currentlyexecuted control mode instructed by said second non-proper conditiondetecting means, to a further separate control mode when non-propercondition of said drive motor has been detected within saidpredetermined period.
 26. An electronic watch comprising: a powersupply; an oscillator circuit; a means for generating a drive pulse; adrive motor which drives a hand, in response to a drive pulse outputfrom said drive pulse generating means; a drive circuit for controllingdrive of said drive motor; and a controlling means for controlling saiddrive circuit; and said electronic watch further comprising; a means fordetecting a non-proper condition which sense an occurrence of acondition in which proper drive of said drive motor is not possibleunder a prescribed condition; means for instructing a change of acontrol mode which instructs said drive circuit controlling means tochange the control mode that is currently being executed, in response toa detection signal output from said non-proper condition detectingmeans, wherein said means for instructing a change of a control modeinstructs said controlling means for controlling said drive circuitmeans to return to the original controlling mode after when said controlmode had been changed and no such detection signal had been output fromsaid non-proper condition detecting means, wherein said drive motorcomprises a first drive motor and a second drive motor and wherein saidnon-proper condition detecting means is a means for monitoring arotating condition of the second drive motor, while said control modechange instructing means is a means for instructing said drive circuitcontrolling means to make the control mode of said first drive motorchanged, in response to said detection signal output from saidnon-proper condition detecting means and further wherein said electronicwatch further comprises a load compensation control system which detectswhether or not said drive motor had been rotated in response to aprescribed drive pulse which is supplied by said drive circuit means andin the case in which a judgment is made that said drive motor had notbeen rotated, which supplies a prescribed compensation drive pulse tosaid drive circuit means, thereby compensating the rotation of saiddrive motor and further wherein said non-proper condition detectingmeans is a means for detecting an estimation electric power level ofsaid power supply which is discriminated by said load compensationcontrol system.
 27. An electronic watch comprising: a power supply; anoscillator circuit; a means for generating a drive pulse; a drive motorwhich drives a hand, in response to a drive pulse output from said drivepulse generating means; a drive circuit for controlling drive of saiddrive motor; and a drive circuit controlling means for controlling saiddrive circuit; and said drive pulse generating means further comprising;a normal hand-drive pulse generation circuit which generates a normalhand-drive pulse and a non-normal hand-drive pulse generation circuitwhich generates a non-normal hand-drive pulse that differs from thenormal hand-drive pulse, and said electronic watch further comprising; ameans for detecting a non-proper condition which sense an occurrence ofa condition in which proper drive of said drive motor is not possibleunder a prescribed condition; and means for instructing a change of acontrol mode which instructs said drive circuit controlling means toprohibit an output of said non-normal hand-drive pulse, in response to adetection signal output from said non-proper condition detecting means;and wherein said non-normal hand-drive pulse is a fast-forward pulse.28. An electronic watch according to claim 27, wherein said drive motorcomprises a first drive motor and a second drive motor and wherein saidnon-proper condition detecting means is a means for monitoring arotating condition of the second drive motor, while said drive circuitcontrolling means for controlling said drive circuit prohibits saidfirst driving motor from being driven by said non-normal hand-drivepulse.
 29. An electronic watch according to any one of claims 24, 26,and 27, wherein said control mode change instructing means, in responseto a detection signal of said non-proper condition detection means,outputs an instruction to said drive circuit controlling means so as tostop the control mode which is currently being executed.
 30. Anelectronic watch comprising: a power supply; an oscillator circuit; ameans for generating a drive pulse; a drive motor which drives a hand,in response to a drive pulse output from said drive pulse generatingmeans; a drive circuit for controlling drive of said drive motor; adrive circuit controlling means for controlling said drive circuit; ameans for detecting a non-proper condition which senses an occurrence ofa condition in which proper drive of said drive motor is not possibleunder a prescribed condition; and a load compensation control systemwhich detects whether or not said drive motor had been rotated inresponse to a prescribed drive pulse which is supplied by said drivecircuit, and in the case in which a judgment is made that said drivemotor had not been rotated, supplies a prescribed compensation drivepulse to said drive circuit means; a control mode change instructingmeans for instructing said drive circuit controlling means to stop saidload compensation control system, in response to a detection signaloutput from said non-proper condition detecting means.
 31. An electronicwatch according to claim 30, wherein said drive motor comprises a firstdrive motor and a second drive motor and wherein said non-propercondition detecting means is a means for monitoring a rotating conditionof the second drive motor, while said drive circuit controlling meansstops said load compensation control system of said first drive motor.32. An electronic watch according to claim 30, wherein said non-propercondition detecting means is a means for detecting electric power whichoutputs a detecting signal in response to a detection of a reduction inpower condition in said power supply.
 33. An electronic watch accordingto claim 30, wherein said drive circuit controlling means suppliespredetermined compensation drive pulse to said drive circuit when saidload compensation control system is stopped.
 34. An electronic watchaccording to claims 26 or 30, wherein said drive pulse generating meanscomprises a normal hand-drive pulse generation circuit means whichgenerates a normal hand-drive pulse and further comprising at least onemeans selected from a group of a low-voltage hand-drive pulse generatingmeans, a fast-forward (high-speed) pulse generation circuit means, alow-voltage fast-forward pulse generating means, a reverse-rotationpulse generation circuit means, and a functional hand drive high-speedpulse generation circuit means.
 35. An electronic watch according toclaims 26 or 30, wherein said drive pulse generating means comprising anormal hand-drive pulse generation circuit means which generates anormal hand-drive pulse and further comprising at least one meansselected from a group of a low-voltage hand-drive pulse generatingmeans, a fast-forward (high-speed) pulse generation circuit means, alow-voltage fast-forward pulse generating means, a reverse-rotationpulse generation circuit means and a functional hand drive high-speedpulse generation circuit means, and further wherein said electronicwatch further comprises a load compensation control system which detectswhether or not said drive motor had been rotated in response to aprescribed drive pulse which is supplied by said drive circuit means andin the case in which a judgment is made that said drive motor had notbeen rotated, which supplies a prescribed compensation drive pulse tosaid drive circuit means, thereby compensating the rotation of saiddrive motor and further wherein said compensation drive pulse beingincluded in at least one means selected from said normal hand-drivepulse generation circuit means, said fast-forward (high-speed) pulsegeneration circuit means, said reverse-rotation pulse generation circuitmeans, and said functional hand drive high-speed pulse generationcircuit means.
 36. An electronic watch according to any one of claims24, 26, 27 and 30, wherein said control mode change instructing means,in response to a detection signal of said non-proper condition detectionmeans, outputs an instruction to said drive circuit controlling means soas to change a control mode which is currently being executed to anothercontrol mode.
 37. An electronic watch according to any one of claims 24,26, 27 and 30, wherein said control mode change instructing means, inresponse to a detection signal of said non-proper condition detectionmeans, outputs an instruction to said drive circuit controlling means soas to replace a drive pulse used in the control mode currently beingexecuted to another drive pulse.
 38. An electronic watch comprising: apower supply; an oscillator circuit; a means for generating a drivepulse; a drive motor which drives a hand, in response to a drive pulseoutput from said drive pulse generating means; a drive circuit forcontrolling drive of said drive motor; a drive circuit controlling meansfor controlling said drive circuit; a means for detecting a non-propercondition which senses an occurrence of a condition in which properdrive of said drive motor is not possible under a prescribed condition;and a load compensation control system which detects whether or not saiddrive motor has been rotated in response to a prescribed drive pulsewhich is supplied by said drive circuit, and in the case in which ajudgment is made that said drive motor has not been rotated, supplies aprescribed compensation drive pulse to drive circuit controlling means;and further wherein said drive pulse generating means comprises at leastone pulse generation circuit means selected from a circuit means groupconsisting of a normal hand-drive pulse generation circuit means, afast-forward (high-speed) pulse generation circuit means, areverse-rotation pulse generation circuit means and a functional handdrive pulse generation circuit means and wherein said selected pulsegeneration circuit means generates a plurality of types of drive pulseshaving mutually different drive capacities from each other.
 39. Anelectronic watch according to any one of claims 24, 26, 27, 30 and 38,wherein said electric power of said power supply is varied with thepassage of time.
 40. An electronic watch according to any one of claims24, 26, 27, 30 and 38, wherein said power supply comprises one typeselected from a titanium-lithium battery, a large capacitance condenser,a secondary battery and a solar battery.
 41. An electronic watchaccording to claim 38, wherein said watch is provided with a pulseselection circuit which can select one driving pulse among saidplurality of types of driving pulses.
 42. An electronic watch accordingto claim 41, wherein said pulse selection circuit determines a selectioncondition for selecting one of said driving pulses with reference tosaid load compensation control system.
 43. An electronic watchcomprising: a power supply; an oscillator circuit; a means forgenerating a drive pulse; a drive motor which drives a hand, in responseto a drive pulse output from said drive pulse generating means; a drivecircuit for controlling drive of said drive motor; and a drive circuitcontrolling means for controlling said drive circuit; and said drivepulse generating means further comprising; a normal hand-drive pulsegeneration circuit which generates a normal hand-drive pulse and anon-normal hand-drive pulse generation circuit which generates anon-normal hand-drive pulse that differs from the normal hand-drivepulse, and said electronic watch further comprising; a means fordetecting a non-proper condition which sense an occurrence of acondition in which proper drive of said drive motor is not possibleunder a prescribed condition; and means for instructing a change of acontrol mode which instructs said drive circuit controlling means toprohibit an output of said non-normal hand-drive pulse, in response to adetection signal output from said non-proper condition detecting means;and wherein said non-normal hand-drive pulse is a reverse rotationpulse.